At issue in this case is the methodology by which multi-state taxpayers are to compute their liability for franchise and excise taxes to Tennessee and, specifically, the authority of the Commissioner of Revenue to require the taxpayers to use an apportionment methodology other than the standard cost of performance methodology codified in Tenn. Code Ann. §§ 67-4-2012 and 67-4-2110. Plaintiffs, taxpayers that provide wireless communication and data services within and without Tennessee, contend they are entitled to apportion their receipts (income) based upon Tennessee’s standard apportionment formulas because the majority of their “earnings producing activities” occurred in a state other than Tennessee. The Commissioner of Revenue disagreed, insisting that Plaintiffs’ approach, even if statistically correct and derived from the language of Tenn. Code Ann. § 67-4-2012(i)(2), fails to meet the higher goal of fairly representing the business Plaintiffs derive from Tennessee. For this reason the Commissioner, acting pursuant to Tenn. Code Ann. § 67-4-2014(a), varied the standard formula requiring Plaintiffs to include “as Tennessee sales” its receipts from service provided to customers with Tennessee billing addresses. The trial court affirmed the decision. In this appeal, Plaintiffs contend the Commissioner does not have authority to impose a variance unless “unusual fact situations,” which are unique to the particular taxpayers, produce “incongruous results” unintended by Tenn. Code Ann. § 67-4-2012; they also insist that no unusual fact situations exist and that no incongruous results occurred when the statutorily-mandated cost of performance methodology was applied. We have determined that the Commissioner acted within the scope of the discretion granted to him by the statutes and rules. Therefore, we affirm the trial court’s decision.