(a) When the commission, after an investigation and hearing, finds that a rate demanded, observed, charged, or collected by a pipeline carrier for a service, subject to the jurisdiction of the commission, or that a classification, rule, regulation, practice, or contract affecting the rate, is unjust, unreasonable, unduly discriminatory or preferential, the commission shall determine a just and reasonable rate, classification, rule, regulation, practice, or contract to be observed or allowed and shall establish it by order.
(b) If an investigation is conducted in multiple phases, the commission may establish a rate at the end of a single phase. The rate established at the end of a single phase is to be considered a final rate under AS 42.06.400. If the rate established at the conclusion of the proceeding under (a) of this section or after judicial review is less than the rate established after a single phase of an investigation, a shipper is entitled to a refund of the difference between the amounts paid by the shipper and the amounts that would have been paid under the rate established at the conclusion of the proceeding or after judicial review. If the rate established at the conclusion of the proceeding under (a) of this section or after judicial review is more than the rate established after a single phase, a pipeline carrier is entitled to a payment of the difference between the amounts paid to the carrier and the amount that would have been paid under the rate established at the conclusion of the proceeding or after judicial review.