Full Opinion

06/23/2026 DA 25-0673 Case Number: DA 25-0673 IN THE SUPREME COURT OF THE STATE OF MONTANA 2026 MT 132 IN RE: KENNETH E. O’BRIEN, PERSONAL REPRESENTATIVE OF THE ESTATE OF MAXINE O’BRIEN, DECEASED, AND THE C. MARK HASH AND THERESE FOX HASH REVOCABLE FAMILY TRUST, Petitioners and Appellants, v. MONTANA DEPARTMENT OF REVENUE, Respondent and Appellee. APPEAL FROM: District Court of the Eleventh Judicial District, In and For the County of Flathead, Cause No. DV-15-2025-430(B) Honorable Paul Sullivan, Presiding Judge COUNSEL OF RECORD: For Appellants: Therese Fox Hash, Hash, Rudbach, Hutchison & Murray, Kalispell, Montana For Appellee: Nicholas J. Gochis, Senior Tax Counsel, Montana Department of Revenue, Helena, Montana Submitted on Briefs: May 6, 2026 Decided: June 23, 2026 Filed: __________________________________________ Clerk Justice Katherine M. Bidegaray delivered the Opinion of the Court. ¶1 In 2024, taxpayers Kenneth O’Brien, as personal representative for the estate of Maxine O’Brien, and the Mark and Therese Hash Revocable Family Trust (Hash Family Trust) (collectively, O’Brien), appealed the Montana Department of Revenue’s (MDOR) adjusted appraisal of their property for the 2023/24 tax cycle to the Flathead County Tax Appeal Board (CTAB). When CTAB decided the appeal in O’Brien’s favor, MDOR appealed to the Montana Tax Appeal Board (MTAB), which reversed CTAB. O’Brien then sought judicial review of MTAB’s decision, which the Montana Eleventh Judicial District Court affirmed in July 2025. O’Brien appeals. ¶2 O’Brien raises numerous issues, which we summarize and restate as follows: 1. Whether MTAB improperly considered the validity and reliability of O’Brien’s appraisal for the first time on appeal or conducted a “trial de novo” on that issue. 2. Whether MTAB correctly denied O’Brien’s motion for summary judgment. 3. Whether MTAB correctly construed Admin. R. M. 2.51.307(4). 4. Whether “sufficient, relevant information on income” was “made available to the department” under § 15-8-111(5), MCA. 5. Whether MTAB correctly reversed CTAB’s decision. We affirm the District Court’s July 15, 2025 order to the extent it concluded MTAB could consider the validity and reliability of O’Brien’s appraisal and correctly affirmed MTAB’s denial of O’Brien’s motion for summary judgment; reverse the District Court’s order to the extent it affirmed MTAB’s February 2025 merits decisions; reverse MTAB’s 2 February 2025 merits decisions; and reinstate CTAB’s April 2024 decisions for Units 130, 132, and 136. FACTUAL AND PROCEDURAL BACKGROUND ¶3 O’Brien’s case has a complicated factual and procedural history. The dispositive statutory question, however, is straightforward: whether, at the time of MDOR’s informal review of its 2023/24 assessment, “sufficient, relevant information on income was made available to the department.”1 If the answer was yes, MDOR had to use the income approach to appraise O’Brien’s commercial condominiums. If the answer was no, MDOR had to use the cost approach. Section 15-8-111(4), (5)(b), (c), MCA. With this governing question in mind, we discuss the relevant factual and procedural history of this case. The subject property: PWI Units 130, 132, and 136 ¶4 The subject property, Plaza West I (PWI), is a commercial condominium building located in Kalispell, Montana. PWI was built in 1973 and has five individual units. The owners of two units, 126 and 128, were parties to the CTAB and MTAB proceedings below, but these unit owners did not seek judicial review of MTAB’s decision and are therefore not parties to this appeal. The remaining units are: 130 and 132,2 formerly owned by Maxine O’Brien and now by her estate, and 136, owned by the Hash Family Trust. 1 This case does not require us to decide whether MDOR generally may rely on mass-appraisal models when valuing commercial property. The narrower question is whether MDOR may treat the absence of model data for commercial condominiums as dispositive when the taxpayer has made income information available that bears directly on the subject property and comparable rental property. 2 Due to mislabeling while condominiumizing, Unit 132 is sometimes alternatively called Unit 134. 3 Below, the parties consolidated proceedings on all units because everything is materially the same between them except for their square footage. O’Brien used Unit 130 as the prototypical example and so will we. ¶5 Each PWI unit has its own basement with individual access via stairs, and each unit rents the first floor and basement together. The basements generally mirror the upstairs floor plans, and one cannot access the basement of one unit from the basement of another, though some of the basement space is apparently also common area. The basements are not separately rentable, however, because of fire code and access only through the first floor. They are used primarily for storage, though some have mixed-used office space. ¶6 Plaza West II (PWII) is located immediately adjacent to PWI and was built shortly after by the same builder using the same plans and same materials. The only substantive differences between the two buildings are that PWII has more individual units configured slightly differently and is not condominiumized. Like PWI, PWII units also each have full basements accessible only via the first floor and the first floor and basements are rented together. MDOR’s 2021 assessment on PWI Condominiumization and O’Brien’s 2022 CTAB appeal ¶7 The events underlying this case began when O’Brien condominiumized PWI in 2021. According to O’Brien, in 2020, MDOR appraised PWI using the income approach to valuation, as it always had.3 But O’Brien’s condominiumizing PWI in 2021 triggered a 3 In 2020, MDOR appraised the PWI and PWII buildings each at $697,900. 4 mid-cycle reappraisal.4 Using the income approach, MDOR assigned Unit 130 a potential gross income (PGI) of $20.50/square foot (s.f.)5 for the first floor only and did not value the basement separately. Believing the $20.50 PGI was “vastly in excess of what it should be,” O’Brien sought MDOR informal review. On informal review, MDOR reassessed and reduced the first-floor PGI to $15.50 but then, for the first time ever, valued the basement separately at a PGI of $8.75. When O’Brien asked MDOR to supply the basis for its PGI numbers, MDOR supplied only information on comparable sales, not comparable rents. ¶8 Maxine O’Brien and the Hash Family Trust appealed MDOR’s assessments for Units 130, 132, and 136 to CTAB, arguing MDOR could not separately value the basements because they were not separately rentable due to their being accessible only through the upstairs of each unit and not up to fire code. In 2022, CTAB accepted O’Brien’s and the Hash Family Trust’s proposed income-approach valuations, which valued the unit first floors only. The only record before this Court of CTAB’s 2022 decisions are three November 16, 2022 letters from the CTAB secretary, one each for Units 130, 132, and 136, describing the decision as “correcting the valuation by adjusting the total valuation” for each unit to the taxpayers’ valuation.6 4 “Each unit of a condominium project is considered a parcel of real property subject to separate assessment and taxation.” Section 15-8-511(1), MCA; see also Title 70, chapter 23 (Montana’s “Unit Ownership Act” governing condominiumizing). 5 PGI is a component of the net operating income calculus and equals the monthly rent times 12 months divided by the “income area” square footage. All references to PGI throughout are to the potential gross income per square foot. See Admin. R. M. 42.20.108(1)(b) (2005); MDOR’s CTAB Exhibit B, pp. 12-13 (calculating PGI based on the “square foot model”). 6 For example, CTAB valued Unit 130 at O’Brien’s proposed $145,438, down from MDOR’s $474,000. 5 ¶9 MDOR admits that CTAB found in O’Brien’s favor in 2022 and that it did not appeal CTAB’s 2022 decisions. The 2023/24 appraisal and O’Brien’s request for MDOR informal review ¶10 After the 2022 CTAB decisions, MDOR assessed PWI for the 2023/24 tax cycle. In June 2023, again using the income approach, MDOR assigned Unit 130 a first-floor PGI of $14.75 and a basement PGI of $9.00. ¶11 In July 2023, O’Brien asked for MDOR informal review under § 15-7-102(3)(a)(ii), MCA.7 O’Brien said MDOR’s $14.75 first-floor PGI was too high and that MDOR could not separately value the basements under the 2022 CTAB decisions. Like in 2021, O’Brien asked MDOR to “provide all comparable rental properties and rent used in making the assessment.” See § 15-7-102(3)(b), MCA. MDOR later confirmed that it never provided the taxpayers this requested information. ¶12 To support the taxpayers’ proposed income valuations, O’Brien provided MDOR with a “Taxpayers’ Appraisal” worksheet showing values for each PWI unit. O’Brien later submitted a more formal “Report and Appraisal” dated October 27, 2023, and authored by Jeff O’Brien (Jeff), a CPA and Ken and Maxine O’Brien’s son. The appraisal explained its methodology, which calculated value using MDOR’s income-approach formula, as 7 Section 15-7-102(3)(a)(ii) prescribes a taxpayer request for “informal classification and appraisal review” of “class four property described in 15-6-134,” also known as a Form AB-26. 6 provided in Admin. R. M. 42.20.108 (2005),8 and a first-floor-only $12.59 PGI developed from actual PWI rents and rents from the nearly identical PWII. ¶13 On January 17, 2024, MDOR sent O’Brien a determination letter regarding its decision on informal review. MDOR indicated it had adjusted the property value based on a “change to property information.” MDOR lead appraiser Andrew Pritchard would later testify that this “change” was to the use code for PWI basements from “office” to “storage.” Though the letter also contained a box for “change in valuation method,” MDOR did not check it.9 ¶14 O’Brien obtained the new property record cards for each unit in February 2024. Unit 130’s record card showed a reduced appraisal value based on the “cost method.” Confusingly, the record card also showed an appraisal value calculated under the “income” method, assigning a first-floor PGI of $14.75 and a basement PGI of $5.50. The total cost-approach and income-approach values were nearly the same amount. MDOR’s Pritchard would later testify that the record card showed an income-approach valuation “by default in the form” as “informational for the property owner”; but he also, somewhat contradictorily, testified that MDOR intentionally reduced the basement PGI from $9.00 8 In its simplest form, the income-approach formula calculates property value (V) as the product of “typical property net income” (I) divided by a capitalization or “cap” rate (R), i.e., V=I/R. In this formula, I is separately calculated by taking the PGI and subtracting an MDOR vacancy discount and allowable expenses. A vacancy discount is a percentage reduction from income for rental vacancy and uncollected rents. R, the cap rate, reflects an income-producing property’s return on investment and is separately calculated by dividing the property’s net operating income by its corresponding valid sale price. Admin. R. M. 42.20.108; 42.20.109 (2002). 9 MDOR’s determination letter further explained “how the department calculated the market value of [PWI units] using the cost approach.” O’Brien would later claim that the taxpayers’ copy of the letter did not contain this language. 7 to $5.50 “in an effort to recognize the property owner’s concerns” about valuing the basements. Despite that the property record cards showed income and cost valuations, Pritchard confirmed MDOR used only the cost approach to value. O’Brien’s 2024 CTAB appeal ¶15 O’Brien appealed MDOR’s adjusted appraisal to CTAB pursuant to §§ 15-7-102(6) and 15-15-102(4), MCA, on the grounds that the $14.75 first-floor PGI was unsupported and that MDOR could not value the basements separately because of the 2022 CTAB decisions which MDOR did not appeal. O’Brien asked CTAB to reduce the unit values to the taxpayers’ valuation amounts as stated in Jeff’s appraisal. ¶16 Prior to the scheduled CTAB hearing, MDOR provided O’Brien with a copy of its cost-approach appraisal wherein MDOR identified its rationale for switching appraisal methods.10 To wit: The property owner states the department has overvalued the Plaza West Condos. In the past, concern was expressed regarding the department’s income value method for some of these units. To avoid that concern for 2023, the department has valued the units on the cost approach. The department selected the cost approach and applied appropriate depreciation as evident in the overall price per square foot. The department recognizes the basement area for each unit does not meet fire code requirements to legally rent as office space. This consideration is evident in the price per square foot . . . for this area. The basement areas are being utilized as either storage or additional office space. 10 O’Brien would later claim that this was the first time the taxpayers learned of MDOR’s switching appraisal methods. MTAB and the District Court rejected any claim of surprise, however, because the property record cards, which Ken O’Brien personally received in February 2024, noted that MDOR had adjusted the 2023/24 appraisal values based on the “cost method.” 8 The department’s valuation is also supported by the sale price of two of the Plaza West units. The sales occurred within six months of the current appraisal date of January 1, 2022. . . . The department is not required to use income data provided by each property owner to then create an income value for each individual property. This would require an individual appraisal of each property every reappraisal [which] would be time-consuming and an impossible task for mass appraisal valuation. The department is required to review any income data provided by an individual property owner to determine if an adjustment is necessary based on the department’s model data. If sufficient, relevant data is not available, the department shall value condominiums using the cost approach to value. The income calculation provided by the property owner . . . is not an appraisal. Choosing to use the property owner’s reported income values, with some of the department’s income model values, overstates expenses and reduces the net operating income below market averages. Determining market value by using only portions of the department’s income calculation model, and then incorporating outside data, is not an acceptable appraisal methodology. . . . The property owner’s calculated NOI, divided by the sales price of either of the two sold units, suggests a much lower cap rate than the department’s modeled cap rate. . . . The property owner’s calculations are not acceptable. The April 2024 CTAB hearing ¶17 Based on MDOR’s asserted rationale, the focus of the April 4, 2024 CTAB hearing became whether MDOR had “sufficient, relevant information on income” and therefore had to use the income approach to value PWI’s commercial condo units as required by § 15-8-111(5)(b), MCA. MDOR said it lacked sufficient information; O’Brien said MDOR had sufficient information because the taxpayers provided it. Noting that MDOR had, at all times prior to the 2023/24 tax cycle, used the income approach, including after 9 condominiumization in 2021, O’Brien suggested that MDOR switched to the cost approach not for lack of data, but to assess the basements separately and thereby circumvent CTAB’s 2022 decisions. O’Brien argued that taxpayer “concerns” could not legitimately justify using the cost approach under § 15-8-111(5), MCA. ¶18 When examined at the hearing, Jeff described himself as PWI’s bookkeeper and property manager; he collected rents and paid building expenses. Though not a certified appraiser, Jeff had over 30 years’ experience as a CPA, including preparing income-based appraisals. ¶19 Jeff testified as to the basis for his income-approach valuation. He explained that he developed the $12.59 PGI from actual PWI and PWII rents in 2021. Prior to their sale in late 2021, Units 126 and 128 rented for $10.62/s.f. Unit 132 rented for $12.59/s.f. Unit 130, which Jeff rented as office space for his CPA firm, rented for $10.37/s.f.11 The average rent rates for PWII’s units was $12.87/s.f. Units in both buildings were rented under similar terms and all rents included use of the basements. ¶20 The taxpayers separately provided an affidavit from PWII part-owner Dennis Green, which corroborated Jeff’s appraisal. Green stated he rented PWII units for an average of $12.87/s.f. based on and competitive with the market and that each unit’s rent included use of the basement, which Green treated as an amenity and not a separately rentable space. 11 Unit 136 was owner-occupied in 2021. 10 ¶21 Jeff explained that he used the “highest” $12.59 PGI to calculate each PWI unit’s value using MDOR’s Rule 42.20.108 income-approach formula. The formula requires inputting values for income, expenses, vacancy discounts, and capitalization rates.12 Initially, Jeff used MDOR model data for all those values except for income, where he used the $12.59 PGI, and expenses, where he used actual PWI expenses and MDOR model expenses where PWI was lacking. But, when MDOR objected to Jeff’s mixing actual and model expense data in his first appraisal (O’Brien’s CTAB Exhibit 9), he prepared a second appraisal (O’Brien’s CTAB Exhibit 15), which used his $12.59 PGI and MDOR’s model data for all other values in the calculus.13 ¶22 MDOR witnesses, lead appraiser Pritchard and regional manager Dawn Cordone, testified as to why MDOR switched from the income to the cost approach: (1) it lacked model income data for comparable properties; (2) O’Brien’s appraisal was neither sufficient nor relevant and was instead unacceptable for several reasons; and (3) the cost approach allowed MDOR to “overcome the property owners’ concerns” about valuing the PWI basements under the income approach while still bringing the overall appraisal value in line with the market. ¶23 As for lack of model data, Cordone testified that income data on commercial condominiums in Kalispell was “limited,” meaning MDOR could not adequately build a mass-appraisal income model for that property type. This was why, when O’Brien 12 See supra, note 8. 13 This resulted in a revised total value for Unit 130 of $275,889, up from $251,951. 11 requested MDOR’s basis for its June 2023 PGIs, MDOR did not provide that information. Cordone did not, however, explain how MDOR derived the PGIs it used in its 2021 and 2023 income-approach appraisals, leaving Ken O’Brien’s testimony that they were based on comparable sales, and not rents, uncontroverted.14 ¶24 As for O’Brien’s appraisal, MDOR did not consider it “sufficient or relevant” for two primary reasons. First, the $12.59 PGI was too low because it did not capture the value of the basements and was the product of bad management practices like renting below market to friends and family. Second, the methodology was flawed because blending PWI’s $12.59 PGI with MDOR’s model data for all other values in the formula resulted in an appraisal value half of the market value, which MDOR knew precisely from the 2021 sales of Units 126 and 128. MDOR said that it could not accept an appraised value half the market value because that would violate the statutory mandate of § 15-8-111, MCA, that MDOR assess all taxable property at 100% market value. MDOR disagreed with O’Brien that § 15-8-111(4) and (5), MCA, the sections for valuing commercial condominiums, permitted assessment below market value. 14 At the later MTAB hearing, Ken O’Brien tried to get MDOR to answer this question. There, he asked Pritchard directly, “If you didn’t have sufficient information to perform an appraisal based on the income approach, how did you use that method?” MDOR objected and Pritchard never directly answered where MDOR came up with the information to perform its June 2023 income approach appraisal; Pritchard did, however, confirm that MDOR never supplied that information to the taxpayers, despite their request. 12 ¶25 MDOR also took issue with Jeff’s qualifications and the fact that the appraisal was dated in October 2023. Notwithstanding these shortcomings, Cordone testified that MDOR fully considered O’Brien’s appraisal on informal review but rejected it. ¶26 Finally, as for MDOR’s switching appraisal methods to resolve taxpayer “concerns” about the basements, Cordone said the basements had some inherent value, at minimum as storage space. But, importantly, Cordone agreed that the basements had no separate, individual, or additional value as income-producing property beyond what was already captured in the rent for the first floor. MDOR’s concern, then, was that O’Brien’s PGI was too low to reflect the basements’ value. By contrast, Cordone and Pritchard explained that the cost approach, which allowed MDOR to value the basements separately, solved that problem. CTAB’s April 2024 decision ¶27 CTAB deliberated on the record. The board concluded that MDOR’s claimed lack of income information was not credible and that the taxpayers had overcome MDOR’s presumption of correctness by providing sufficient, relevant income information. Therefore, CTAB resolved the threshold question in O’Brien’s favor: PWI units had to be valued using the income approach under § 15-8-111(5)(b), MCA. CTAB then compared the taxpayers’ and MDOR’s income-approach appraisals. Noting that O’Brien’s calculation used all MDOR model data except for income, the board focused on the competing PGIs—i.e., “whose figures to use.” ¶28 CTAB decided that O’Brien’s $12.59 PGI was “perfectly” corroborated by Green’s affidavit describing actual rents from the nearly-identical PWII. PWII’s similar rents also 13 refuted MDOR’s claim that PWI’s reported rents were based on improper management practices. And, like PWII’s rents, PWI’s rents reflected use of the basements and therefore captured the basements’ values for taxation purposes. Conversely, the board expressed concern that MDOR’s $14.75 PGI was based on comparable sales, not comparable rents, as required under MDOR’s Rule 42.20.108, and disagreed with assigning any separate PGI to the basements, which had no individual income-producing value. ¶29 After deliberation, CTAB ordered MDOR to apply O’Brien’s income-approach valuation, Exhibit 15, which calculated value by using all MDOR model data and O’Brien’s $12.59 PGI. CTAB issued conforming written decisions for each PWI unit the next day on April 5, 2024. MDOR’s appeal to MTAB; Issues presented ¶30 In May 2024, MDOR appealed CTAB’s decision to MTAB pursuant to §§ 15-2-301 and 15-15-104(1), MCA, initially on the broad grounds that CTAB’s decision was erroneous and its valuation did not comport with the law. At MTAB’s request, MDOR later asserted more specifically that CTAB had erroneously rejected MDOR’s cost-approach appraisal upon concluding that sufficient, relevant information on income was made available, mandating use of the income approach under § 15-8-111(5), MCA. O’Brien’s Motion for Summary Judgment ¶31 In advance of the MTAB hearing, O’Brien filed a motion for summary judgment, claiming entitlement to judgment as a matter of law on the ultimate question of valuation. Within that ultimate issue, however, lay numerous other questions—including the disputed 14 threshold question of whether MDOR had sufficient, relevant income information under § 15-8-111(5), MCA. MDOR said the predicate factual question—whether MDOR’s model data or O’Brien’s property-specific data met the standard—remained disputed, precluding summary judgment. ¶32 The parties also argued over the preclusive effects of the 2022 CTAB decisions which MDOR did not appeal, and specifically whether MDOR could separately value the unit basements. O’Brien said no; MDOR said yes, because Admin. R. M. 2.51.307(4) (2023) creates an exception to the finality of CTAB decisions for circumstances affecting property value, such as periodic reappraisal under § 15-7-111, MCA. ¶33 After full briefing, MTAB concluded that O’Brien was not entitled to summary judgment and denied O’Brien’s motion. The November 2024 MTAB Hearing ¶34 At the November 14, 2024 MTAB hearing, Ken O’Brien testified about the 2022 CTAB proceedings and decisions which MDOR did not appeal and about the history of the 2023/24 appraisal leading to the present MTAB appeal. ¶35 Jeff O’Brien testified in conformance with his CTAB testimony regarding how he prepared his appraisal, and specifically, how he developed the $12.59 PGI by using actual PWI and PWII rental income data, which he personally investigated and confirmed. Jeff conceded he was not a certified appraiser but said that his 30-year accounting background qualified him to prepare the income-approach appraisal. Finally, Jeff addressed MDOR’s management practices concern, denying that he received any “sweetheart deal” because his 15 rent for Unit 130 was comparable with other PWI and PWII units and to office rent he paid elsewhere. ¶36 MDOR’s lead appraiser Pritchard and regional manager Cordone also testified in conformance with their CTAB testimony, namely that MDOR switched to the cost approach because it lacked sufficient modeling data; it wanted to resolve the taxpayers’ concerns that MDOR was overvaluing the basements under the income approach; and the cost-approach valuation “came right in line” with the sale prices for the recently-sold Units 126 and 128. Pritchard and Cordone also offered the same critiques of O’Brien’s appraisal: the PGI was too low; the blending methodology was flawed; Jeff was not an appraiser; and the appraisal was not completed within six months of the pertinent valuation date, January 1, 2022. ¶37 First, as for lack of model income data, Pritchard testified that MDOR’s mass-appraisal data pool for Kalispell included 49 properties, only one of which was a commercial condominium. That property, however, was not comparable because it did not have a basement and was in an inferior location. MDOR therefore lacked sufficient income data to build a model for that property type. ¶38 Second, as for O’Brien’s income data, Pritchard admitted O’Brien provided “income information” for PWI and for the neighboring PWII. But that income information could not be “independently verified” because O’Brien did not provide any tax returns or lease or management agreements; though requested, PWII had also not provided income and expense information; and the only other commercial condo in the data pool was not comparable so MDOR could not use it to verify O’Brien’s PGI. In response to MDOR 16 interrogatories and requests for production ahead of the CTAB hearing, O’Brien disclosed that there were no written rental agreements available because they were verbal leases. ¶39 When asked why MDOR did not use the income information O’Brien provided, Pritchard answered that “the data was not reliable” because of “some inconsistencies with the income information.” Specifically, O’Brien’s “rent rates were below market” and “below what [MDOR] had typically seen for commercial properties.” Pritchard again indicated O’Brien’s rent rates were discounted for friends and family but did not identify anyone besides Jeff O’Brien as related to PWI ownership. Finally, despite possessing PWI and PWII rent data, Pritchard expressly denied that MDOR “had sufficient information to determine what the PGI was” for PWI or PWII. ¶40 Further, MDOR argued for the first time that PWII was not, as O’Brien claimed, an “identical” property because it was wholly owned and not condominiumized. But the only effect of this distinction, according to Cordone, was that PWI condos and the PWII building had different market values. Cordone admitted, however, that because of their similarities, PWI and PWII may “garner . . . the same market rent.” ¶41 Finally, as before CTAB, market value was the primary asserted reason for both rejecting O’Brien’s appraisal and switching to the cost approach. Above all other shortcomings, O’Brien’s appraisal resulted in unit values that were half their market value, which MDOR found unacceptable and inequitable. By comparison, MDOR said the cost approach solved this problem because it “recognized the reduced utility” of the basement spaces, reduced the overall assessment, “came right in line with the sales prices” 17 of Units 126 and 128, and therefore was “the most appropriate and defensible approach to valuation.”15 MTAB’s February 2025 decision ¶42 On February 5, 2025, MTAB issued its decisions, reversing CTAB and adopting MDOR’s cost-approach assessments for all PWI units. As pertinent to our analysis, MTAB made the following conclusions of law: (1) “Under Montana law, [MTAB] may hear cases de novo and may affirm, reverse, or modify a CTAB decision.” (2) O’Brien’s “valuation” was not “an appraisal” because “it was performed more than six months after the valuation date” and “because it mixed” actual PWI information with MDOR model information, “result[ing] in an unreliable value.” (3) “Because MDOR performs mass appraisals, they cannot use a property’s actual income and expense data to value that property.” That would require “a separate appraisal for each commercial property” which is “not feasible.” (4) MDOR “determined it did not have sufficient information to use the income approach to value [PWI] because only one of the voluntary submissions of income information they received was from a commercial condominium,” but that property “was in an inferior location and lacked a basement.” (5) “If MDOR does not receive sufficient information to value a particular commercial property using the income approach, which can happen when there are not enough voluntary submissions of data to develop a model, MDOR must value the property using the cost approach.” 15 MDOR’s Pritchard testified in support of MDOR’s cost-approach appraisal and O’Brien tested Pritchard’s assessment methodology on cross-examination. MDOR modeler Jake Thiesen testified about the land value modeling data underlying the cost-approach appraisal. O’Brien stipulated, for purposes of the cost approach, that MDOR’s model was accurate and met all required standards. 18 (6) “If MDOR receives sufficient income information from voluntary submissions in a future cycle,” it “may value [PWI] using the income method.” (7) “Because MDOR only received income information from one commercial condominium during the 2023/24 valuation cycle,” MDOR “correctly valued the property using the cost approach.” (8) MDOR was not “prohibited from valuing the basements” under the 2022 CTAB decisions because, under Admin. R. M. 2.51.307(4), “each valuation cycle stands on its own.” O’Brien’s petition for judicial review of MTAB’s decisions on Units 130, 132, and 136 ¶43 In March 2025, O’Brien sought judicial review of MTAB’s decisions pursuant to §§ 15-2-303, 2-4-702, and -704, MCA, asking the court to reverse MTAB’s decisions and reinstate CTAB’s decisions. O’Brien identified four primary issues, whether (1) CTAB erred; (2) MTAB erroneously decided the case based on an issue not presented on appeal; (3) MTAB erroneously tried the case “de novo”; and (4) MTAB erroneously denied O’Brien’s motion for summary judgment. ¶44 The District Court identified the “heart of the issue” as whether the income- or cost-approach appraisal method applied. The court concluded that substantial record evidence showed MDOR lacked sufficient, relevant income information and therefore that the “threshold condition” triggering mandatory use of the income approach was not met and that MTAB did not err in adopting MDOR’s cost-approach appraisal. From there, the court also concluded that MTAB did not consider new issues beyond the scope of appeal; MTAB had authority under § 15-2-301, MCA, and Mont. Dep’t of Revenue v. Burlington N., 169 Mont. 202, 545 P.2d 1083 (1976), to hear appeals from MTAB 19 “de novo”; and MTAB correctly denied O’Brien’s motion for summary judgment. The District Court affirmed MTAB’s decisions on July 15, 2025. O’Brien appeals. STANDARD OF REVIEW ¶45 Section 2-4-704, MCA, sets forth the standards for judicial review of agency decisions, permitting modification or reversal of the agency decision if the petitioner’s substantial rights were prejudiced because: (a) the administrative findings, inferences, conclusions, or decisions were: (i) in violation of constitutional or statutory provisions; (ii) in excess of the statutory authority of the agency; (iii) made upon unlawful procedure; (iv) affected by other error of law; (v) clearly erroneous in view of the reliable, probative, and substantial evidence on the whole record; or (vi) arbitrary or capricious or characterized by abuse of discretion or clearly unwarranted exercise of discretion. Section 2-4-704(2)(a), MCA. ¶46 Under this standard, agency findings are reviewed for clear error and conclusions of law for correctness. GBN, Inc. v. Mont. Dep’t of Revenue, 249 Mont. 261, 264, 815 P.2d 595, 596-97 (1991); Flathead Lakers Inc. v. Mont. Dep’t of Nat. Res. & Conservation, 2023 MT 85, ¶¶ 33-35, 412 Mont. 225, 530 P.3d 769. Agency factual findings are clearly erroneous if unsupported by substantial record evidence, if the agency misapprehended the effect of the substantial evidence, or if review leaves the court with a firm conviction a mistake was made. Flathead Lakers, ¶ 34; Peretti v. Mont. Dep’t of Revenue, 2016 MT 105, ¶¶ 17-18, 383 Mont. 340, 372 P.3d 447. 20 ¶47 This Court reviews district court decisions on judicial review of agency decisions applying the same § 2-4-704, MCA, standards. Flathead Lakers, ¶ 35; Peretti, ¶ 15. Reviewing courts “may not re-weigh the evidence or re-determine witness credibility to achieve a different result.” Peretti, ¶ 17; § 2-4-704(2), MCA. We must review the entire administrative record, giving deference to agency findings only if not clearly erroneous and to agency determinations only insofar as they are lawful and the product of consistent, rational, well-supported, and cogently-explained decision-making. DeBuff v. Mont. Dep’t of Nat. Res. & Conservation, 2021 MT 68, ¶ 24, 403 Mont. 403, 482 P.3d 1183; Puget Sound Energy, Inc. v. State, 2011 MT 141, ¶¶ 15-16, 361 Mont. 39, 255 P.3d 171. ¶48 When reviewing decisions of the Montana Tax Appeal Board, we recognize that the board “is particularly suited for settling disputes over the appropriate valuation of a given piece of property.” O’Neill v. Mont. Dep’t of Revenue, 2002 MT 130, ¶¶ 22-23, 310 Mont. 148, 49 P.3d 43; Peretti, ¶¶ 14, 17-18. Because tax assessments are within MTAB’s specific expertise, we will uphold them “unless there is a clear showing of an abuse of discretion.” O’Neill, ¶ 23; Dep’t of Revenue v. Grouse Mt. Dev., 218 Mont. 353, 355-56, 707 P.2d 1113, 1115 (1985). An abuse of discretion occurs where MTAB misapplies the controlling law or exercises discretion based on clearly erroneous findings of fact. See Bessette v. Bessette, 2019 MT 35, ¶ 13, 394 Mont. 262, 434 P.3d 894; accord Flathead Lakers, ¶ 34 (agency decisions are arbitrary or capricious if at odds with the information gathered or the product of internally inconsistent analysis). ¶49 Agency interpretations, applications, and conclusions of law are reviewed de novo for correctness. Flathead Lakers, ¶ 35. While we afford an agency’s interpretation of 21 statutes it administers “respectful consideration,” administrative interpretations are not binding on this Court. Mont. Power v. Mont. PSC, 2001 MT 102, ¶¶ 24-27, 305 Mont. 260, 26 P.3d 91. ¶50 This appeal does not require us to substitute our judgment for MTAB’s appraisal expertise or to reweigh competing valuation evidence. Rather, it requires us to determine whether MTAB and the District Court correctly construed and applied the statutory threshold in § 15-8-111(5), MCA. MTAB’s valuation expertise receives deference when it weighs evidence under the correct legal standard. It does not receive deference when it inserts a requirement into the statute that the Legislature did not include or when it misapprehends the legal effect of undisputed income information made available to MDOR through informal review and appeal. See § 2-4-704(2), MCA; Peretti, ¶¶ 15, 17; Flathead Lakers, ¶¶ 34-35; Mont. Power, ¶¶ 24-27. DISCUSSION ¶51 1. Whether MTAB improperly considered the validity and reliability of O’Brien’s appraisal for the first time on appeal or conducted a “trial de novo” on that issue. ¶52 Issue framing became an issue here when MDOR appealed to MTAB. However, as stated above, the threshold dispositive question before CTAB and MTAB was the same: whether “sufficient, relevant information on income [was] m