If the method of apportionment provided for in § 12-251, § 12-258 or § 12-265 unfairly attributes to this state an undue proportion of its business activity, a company or municipal utility, as defined in § 12-265, may petition for an alternate method of apportionment by filing with its return to the commissioner a statement of its objections and of such proposed other method of apportionment as it believes proper and equitable under the circumstances, accompanied by supporting details and proofs. The commissioner, within a reasonable time thereafter, shall notify the company or municipal utility whether the proposed method is accepted as reasonable and equitable and, if so accepted, shall adjust the return and tax accordingly. With respect to any company included in § 12-249, § 12-256 or § 12-264, or municipal utility, as defined in § 12-265, the commissioner, at any time within three years after the filing by it of a return based on the method of apportionment provided for in § 12-249, § 12-258 or § 12-265, may change such method if, in his opinion, such method has operated or will operate so as to subject the company or municipal utility to taxation on a lesser portion of its business activity than is properly and equitably attributable to this state, and shall thereupon proceed to assess and collect taxes in accordance with such method as so changed by him.