In the event that a utility is ordered to refund any revenues by a governmental entity or agency with jurisdiction to make such an order and the refund will affect the privilege tax paid pursuant to this chapter, the calculation of the privilege tax shall not include the refund except pursuant to a mutually agreed upon schedule. If there is a substantial budgetary impact to the City, the schedule may include spreading the impact of the refund on the future privilege tax to be paid to the City over a period of time commencing the 1st full fiscal year following the ordering of the refund. The schedule shall minimize the administrative impact to the utility and may include interest on the unpaid refund. This section does not apply to credits or other rate adjustments that regularly occur pursuant to a utility’s OPUC approved tariff schedules.