(a) In the event that the amount of the surcharge permitted by the order of the Arkansas Public Service Commission is subsequently determined to have been inadequate, either on rehearing or in accordance with a court decision on judicial review, the public utility subject to such an order shall be entitled to impose an additional surcharge on the affected customers to recover that portion of the surcharge which was not approved by the commission which should have been collected during the period between the effective date of the initial order and the final determination or rehearing or by the court on judicial review.
(b) The surcharge shall be assessed over a period equal to the period between the date of the initial order and the effective date of the final determination on rehearing or by the court on judicial review.
(c) The surcharge shall be distributed among the affected customers in proportion to the amounts those customers were charged during the period between the date of the initial order and the final determination on rehearing or by the court on judicial review.