15-31-312. Apportionment formula -- unitary business provisions. (1) If the allocation and apportionment provisions of this part do not fairly represent the extent of the taxpayer's business activity in this state, the taxpayer may petition for or the tax administrator may require, in respect to all or any part of the taxpayer's business activity, if reasonable:
(a) separate accounting, provided the taxpayer's activities in this state are separate and distinct from its operations conducted outside this state and are not a part of a unitary business operation conducted within and without this state; or
(b) the application of the provisions of Article IV, subsections (18)(a)(ii) through (18)(a)(iv), of 15-1-601.
(2) If the allocation and apportionment provisions of this part do not fairly represent the extent of business activity in this state of taxpayers engaged in a particular industry or in a particular transaction or activity, Article IV, subsection (18)(b), of 15-1-601 applies.