¶ 1 Maricopa County (“County”) appeals the summary judgment determination that it had engaged in tax valuation discrimination. The Appellees (“Taxpayers”) challenge the trial court’s order awarding limited attorneys’ fees and costs. For the following reasons, we affirm the trial court’s judgment but vacate and remand the costs award for further proceedings,
FACTUAL AND PROCEDURAL BACKGROUND
¶ 2 Taxpayers sued the County for property tax discrimination in violation of the Uniformity Clause of the Arizona Constitution. See Ariz. Const, art. 9, § 1 (“[A]ll taxes shall be uniform upon the same class of property within the territorial limits of the authority levying the tax.”). Taxpayers alleged that, for the 1995-1996 tax period, 1 the County discriminatorily valued their apartment buildings at 100% of their full cash value while rolling over valuations on similar properties, which resulted in valuations of less than full cash value.
¶ 3 Taxpayers successfully moved for summary judgment in 1997 because the County had settled similar claims with other taxpayers. We reversed the judgment in part because the County was allowed to settle other tax discrimination suits.
Aida Renta Trust v. Ariz. Dep’t of Revenue,
¶ 4 The parties stipulated to postpone the second remand until after the Arizona Supreme Court acted on our decision. After our decision was vacated in
Aileen H. Char Life Interest v. Maricopa County,
DISCUSSION
I. Tax Discrimination
¶ 5 The County argues that it did not violate the Uniformity Clause when it valued Taxpayers’ properties and that summary judgment was inappropriate. We review a summary judgment de novo to determine if there were any genuine issues of material fact and if the trial court correctly applied the law.
Guo v. Maricopa County Med. Ctr.,
¶ 6 Arizona’s Uniformity Clause mandates that “all taxes shall be uniform upon the same class of property within the territorial limits of the authority levying the tax.” Ariz. Const. art. 9, § 1. The Uniformity Clause prohibits discriminatory valuation among “similarly situated properties”
3
causing some properties “to bear a disproportionate share of the property tax burden.”
Aileen Char,
A. Tax Treatment Applies to the Initial Valuation by the County
f 7 The County contends that tax discrimination only applies to either final tax values or taxes actually paid and not to the initial values 4 relied upon by Taxpayers. 5 The County relies on Aileen Char, which states:
[I]t is the tax paid, not the numerical values assigned to property, that must be uniform. Accordingly, to prevail in a valuation discrimination case, a plaintiff must show tax treatment greatly unequal to that afforded others in the same class and must do so by reference to full cash value.
¶ 8 No case defines “tax treatment.”
6
We do not assume, as the County does, that tax treatment occurs only when a tax bill is sent. Tax treatment must include valuation because
Aileen Char
was a valuation discrimination case looking for “greatly disproportionate valuation.”
Id. Aileen Char
expressly distinguished discriminatory
¶ 9 The County next argues that Aileen Char requires evidence based on the final tax rolls that reflect changes from valuation appeals. As a result, the County contends that 1213 properties favorably valued below full cash value must be eliminated from the class-wide analysis because they were independently appealed, thus absolving the County of responsibility for their final values. 7 Similarly, it argues that 727 favorably treated properties’ values had to be rolled over pursuant to A.R.S. § 42-247 (1991), 8 again absolving the County of responsibility.
¶ 10
Aileen Char
seemingly supports the County when it states “ ‘[valuation’ refers to
the final
value placed upon a piece of property by the taxing authority.”
¶ 11 Moreover, there are two practical problems with the County’s argument that final tax values are needed to demonstrate tax discrimination. First, final values may be initial values that were resolved through the administrative appeals to the assessor; an officer of the “authority levying the tax.”
See
Ariz. Const. art. 12, § 3. Those appeals, however, require evidence from the date of the initial valuation.
See SMP II Ltd. P’ship v. Ariz. Dep’t of Revenue,
¶ 12 Second, if a taxpayer is unhappy -with the administrative appeal, the taxpayer can seek relief on appeal to the State Board of Equalization 9 or the tax court. 10 A taxpayer would need evidence from the initial valuation to challenge the evaluation. Moreover, it would also be difficult to discern the assessor’s intent when viewed through the filter of the valuation appeal process, even though values reduced on appeal tend to support an inference that the valuation was discriminatory. Consequently, evidence surrounding the initial valuation is necessary to demonstrate any tax discrimination.
B. The County Acted Deliberately and Systematically
¶ 13 The County argues that it did not act deliberately and systematically when it valued many of the properties in the favored class because it made a mistake. Tax
¶ 14 We have previously found the “essentially identical factual scenario” of Aileen Char to be “analytically indistinguishable” from the present case. The County opines that we have never held it discriminated against the taxpayers. Our previous remands, however, were on different issues. At no point have we ever stated that the County’s conduct here was significantly different from its conduct in Aileen Char. In fact, our second remand was premised on the similarity of the conduct. Aileen Char affirmed the tax court’s finding that the County’s conduct, essentially the same in both cases, qualified as deliberate and systematic. The only issue Aileen Char did not foreclose is whether a great inequality existed because of different properties and different valuations in each case.
¶ 15 The County contends that our comparison with
Aileen Char
occurred before it attempted to introduce newly discovered evidence of a coding mistake in either case.
11
The County introduced the evidence in its Arizona Rule of Civil Procedure 60(c) motion in
Aileen Char,
¶ 16 We agree with the trial court. The County cites only our first decision in this case as support for exempting its conduct due to mistake. Our earlier decision stated that conduct challenged under the Uniformity Clause must “result from ‘systematic and intentional discrimination’ and not merely from random mishap, ‘oversight,’ ‘negligence,’ or bungling.”
Aida,
¶ 18 The County offered the affidavit of Sara Esser, an appraiser employed by the County, to establish the mistake. Taxpayers assert this affidavit is inadmissible because it is incompetent and speculative.
¶ 19 “[E]xpert opinion evidence based on sheer speculation is not competent.”
State v. Hollis,
¶ 20 Ms. Esser’s affidavit stated that she did not know exactly what happened. She bases her conclusions solely on the existence of the incorrect codes, and she admits that she could not find anyone with personal knowledge of the coding. She also admitted that “[w]hat is not known is whether Application Services wrote the wrong code down or assessor personnel told Application Services the wrong code.” Although she assumes that one of these two errors was the cause for the disparate treatment, her speculation cannot be used as evidence.
¶ 21 We find, as a result, that there was no genuine issue of material fact regarding the County’s intentional and systematic conduct. The County’s “mistake” evidence would be insufficient to cause reasonable jurors to come to a different conclusion. Thus, we sustain the summary judgment as to intentional and systematic conduct. 14
C. The County’s Conduct Caused a Great Inequality
¶ 22 The County next contends that, even if its conduct was deliberate and systematic, there was no resulting great inequality. Taxpayers must prove that deliberate and systematic discriminatory conduct created a great inequality between the values assessed for their properties and for the favored propеrties.
See Aileen Char,
¶ 23 The County repeatedly emphasizes that only 1.8% of the class were favored by its conduct. The percentage has no bearing on the great inequality determination. In prior cases, tax discrimination has been proven when as few as one taxpayer was negatively affected.
See, e.g., In re Am. W. Airlines, Inc.,
¶ 24 The County further relies on a sales ratio comparison offered to show that the assessed values were accurate and did not create a great inequality. The proffered evidence, however, cannot survive summary judgment. See
Orme Sch. v. Reeves,
¶ 25 The County compared sales ratio information provided by the Arizona Department of Revenue (“ADOR”) with its own ratios for the taxpayers’ properties.
15
¶ 26 The trial court found the existence of a great inequality. The taxpayers’ properties were valued at 100% of full cash value, while the favored properties were valued at 56% of full cash value. As a result, the court did not err in finding a great inequality. 16
II. Attorneys’ Fees and Expert Witness Expenses Under § 12-348
¶ 27 Taxpayers argue that the trial court erred by limiting its award of attorneys’ fees, expert witness expenses, and costs. We review the award for abuse of discretion and will reverse if the trial court erred as a matter of law.
Charles I. Friedman, P.C. v. Microsoft Corp.,
¶ 28 Taxpayers who are successful in an action challenging their taxes may recover their “fees and other expenses” in addition to recoverable costs. A.R.S. § 12 — 348(B) (2003). “Fees and other exрenses” includes reasonable expert witness expenses and “reasonable and necessary” attorneys’ fees. A.R.S. § 12-348(I)(1). Recoverable fees in a tax challenge are limited to $30,000 “for fees incurred at each level of judicial appeal.” A.R.S. § 12-348(E)(5).
17
The fees cap, however, applies only to attorneys’ fees, not other recoverable expenses.
SMP II Ltd. P’ship,
A. Expert Witness Expenses
¶ 29 Taxpayers first argue that the trial court misconstrued the $30,000 cap to apply to expert witness expenses as well as attorneys’ fees. We clarified in
SMP II
thаt the fees cap of § 12-348 only limits the recovery of attorneys’ fees, not other expenses.
B. Application of the Attorneys’ Fees Cap
¶ 30 Taxpayers next contend they are entitled to recover fees totaling $80,000 because the trial court proceedings on remand are distinct from the original trial court proceeding. The County, in turn, argues that a single cap of $20,000 applies because the lower limit was in effect when this litigation began and all of the trial court proceedings constitute a single “level of judicial appeal.” We address the application of the new attorneys’ fees cap first.
1. Amount of the Attorneys’ Fees Cap
¶ 31 Generally, “[n]o statute is retroactive unless expressly declared therein.” A.R.S. § 1-244 (2002). There is no declaration of retroactivity for the increased fee limit of § 12-348, in stark contrast tо the declaration making § 12-348 applicable to pending cases when it was initially enacted.
¶ 32 Although § 12-348 does not apply retroactively, it does apply to prospectively incurred fees in pending litigation.
See Abril v. Harris,
2. Judicial Levels of Appeal
¶ 33 With the amount of the attorneys’ fees cap determined, the next question is how many distinct levels of appeal exist. Taxpayеrs insist that the trial court proceedings before each subsequent appeal all qualify for separate fee awards. They rely solely on the public policy justification for the fees statute as authority for their interpretation.
¶ 34 We interpret the statute according to its plain meaning because the statutory text is the best evidence of legislative intent.
Ariz. Dep’t of Econ. Sec. v. Reinstein,
¶ 35 This interpretation is reaffirmed when we examine the history of the present case. It is unlikely that the legislature intended for a taxpayer to recover fees for a portion of the case if unsuccessful at a later stage.
See 4501 Northpoint L.P. v. Maricopa County,
¶ 36 Taxpayers’ last argument is that the trial court erred by not awarding them all of their claimed costs. Taxpayers submitted $2,695.35 in costs. See A.R.S. §§ 12-332, - 341 (2003). The County’s objection to Taxpayers’ statement of costs was limited to a brief reference to prior costs objections and arguing that the initial fees award was never appealed. The County also attached Judge Mangum’s earlier decision limiting costs to thе first award amount based on the “law of the case” doctrine.
¶ 37 Section 12-341 mandates an award of all recovei'able costs to the “successful pai’ty to a civil action.”
Roddy v. County of Mari-copa,
¶ 38 The “law of the case” doctrine does not apply to the original trial court costs award. The law of the case makes a decision controlling on the same court or a lower-court throughout subsequent stages of trial as long as the evidence and issues do not change.
Ctr. Bay Gardens, L.L.C. v. City of Tempe City Council,
¶ 39 The original costs award pertained to a summary judgment we subsequently reversed. The costs award ceased to exist at that point. Subsequently, the issues of the case changed. Moreover, any increase in statutorily taxablе fees constitutes a change of evidence concerning a costs award. Taxpayers’ other-wise uncontested statement of costs showed increased amounts for court filing fees and service of documents. Considering the extended litigation that has occurred since the first statement of costs was filed, the increased costs may be valid. We vacate the costs award and remand so that the trial court may consider all taxable statutory costs incurred since the action was filed and before the trial court’s decision was final.
III. Attorneys’ Fees on Appeal
¶ 40 Taxpayers request attorneys’ fees and costs on appeal pursuant to A.R.S. §§ 12-348(B) and -349. We award their fees on appeal not exceeding $30,000, pursuant to § 12-348(B) and (E)(5), and costs upon compliance with Arizona Rule of Civil Appellate Procedure 21(c). We do not find the County’s positions on appeal unreasonable and therefore do not award additional fees pursuant to § 12-349.
CONCLUSION
¶ 41 For the foregoing reasons, we affirm in part and vacate and remand in part for-reconsideration of the costs award.
Notes
. The legislаture consolidated 1995 and 1996 into a single tax period for valuation purposes, although taxes were levied in both years. See 1994 Ariz. Sess. Laws, ch. 323, § 49 (2nd Reg. Sess.),
amended by
1995 Ariz. Sess. Laws, ch. 249, § 36 (1st Reg. Sess.);
see generally Forum Dev., L.C. v. Ariz. Dep't of Revenue,
. Taxpayers requested an award of $80,000 for attorneys' fees, $38,865.68 for expert witness expenses, and $2695.35 for taxable costs.
. The parties agree that the relevant class of properties is multifamily residential properties with more than four units and fewer than four stories high, sometimes referred to as ''apartmеnts." These properties are occasionally identified with a property use code (“PUC") of 03xx.
See Aileen Char,
. Initial values, sometimes referred to as "postcard roll values,” are the values initially assessed and mailed to taxpayers before the tax rate is set. Taxpayers then have an opportunity to appeal their valuations. The assessor then revalues properties whose values were appealed, and the taxing authority sets the tax rate. See A.R.S. § 42-16002 (2006).
. The County argument is inconsistent. Although it argues that final values are those "upоn which the taxes are actually paid,” thereby seemingly equating the two concepts, the terms "final tax value” and "taxes paid” are not synonymous.
. Tax treatment may refer to tax-specific treatment, as opposed to appraisal treatment. The supreme court in
Aileen Char
noted that "[l]he requirement that a taxpayer show greatly unequal treatment reflects the fact that the ‘valuation of real property ... is not subject to mathematical certainty' and that the assessment of taxes, therefore, need not be exactly equal.”
. Alternatively, the County argues that 147 of the 228 plaintiff properties were taxed on reduced values obtained through administrative or judicial valuation appeals, not due to values set by the County. The County’s arguments are not limited to whether its conduct is at issue. It also contends that we should look at post-valuation appeals' final values to determine if a great inequality exists.
. This section was repealed by Laws 1997, ch. 150, § 9 (effective January 1, 1999).
. The State Board of Equalization reviews administrative appeals of property tax valuations in Maricopa County, which dоes not have a county board of equalization. See A.R.S. §§ 42-241 and -221.01(A)(2) (Supp.1998) (renumbered, respectively, as §§ 42-16102 and -16157(A) (2006)).
. Valuation may also be appealed administratively, but further appeal goes to the State Board of Equalization or the tax court. See A.R.S. §§ 42-176, —221 (J), and -246 (Supp.1998) (consolidated and renumbered § 42-16056(C) (2006)) (describing alternative administrative and judicial property tax appeal processes).
. The County fully admits it favorably valued 333 properties even if all of its other arguments are accepted. The County also admits that another 1212 propеrties were favored but should not be considered because their valuations were successfully appealed and the final valuations changed. Again, we are concerned with the County’s conduct, as opposed to valuation appeals bodies' conduct, and therefore we look at the initial valuation treatment. We do not foreclose the possibility that these 1545 properties alone are sufficient to show systemátic conduct.
. Although the supreme court in
Aileen Char
upheld the trial court's denial of the Rule 60(c) motion premised on new mistake еvidence,
. Taxpayers argue:
The cause of the decision to code these parcels this way is not at issue in this case. What is at issue is whether the roll-over of these parcels was the result of a deliberate act. Hеre, even Ms. Esser admits it was a deliberate act because all of these parcels received a code "540” that caused them to be rolled-over. All Ms. Esser's affidavit asserts is her opinion that the Assessor should not have rolled them over.
Taxpayers thus imply that a volitional act is equivalent to a “deliberate” act. We disagree. The supreme court only stated that Taxpayers must show that the County's conduct was "purposeful” not that it was done in bad faith.
Aileen Char,
. Because we find this to be a sufficient basis for the summary judgment, we do not address thе application of A.R.S. § 42-247 (2006).
. The sales ratios utilize properties that have been sold during the three previous years and divide their final assessed values by the actual sales values. ADOR's sales ratios used all apartment properties in Maricopa County sold during 1993-1995, although it distinguishes between apartments with twenty-five or more units and those with fewer units. The County's sales ratios used plaintiff properties with twenty-five or more units sold during the same period.
. Because we find no error in the trial court's judgment, we do not consider Taxpayers’ arguments about res judicаta, collateral estoppel, or virtual representation.
. The maximum fee recovery under § 12-348 was raised from $20,000 to $30,000 during the course of this litigation. 2000 Ariz. Sess. Laws, ch. 17, § 1 (2nd Reg. Sess.). Subsection (E) also distinguishes limits on fee awards generally and attorneys' fees awards specifically.
. Taxpayers argue that the Arizona Supreme Court in
Aiken Char
applied the $30,000 cap even though the action was filed when the $20,000 cap was in force.
See Aileen Char,
. "Judicial” distinguishes actions in court from administrative actions, for which the legislature did not intend to permit the award of fees.
See Maricopa County v. Superior Court,
