(a) In the event that the rates set in the order of the Arkansas Department of Transportation subsequently are determined to have been inadequate, either on rehearing or in accordance with court decision on judicial review, the public utility subject to the order shall be entitled to impose a surcharge on the affected customers for collection of the increased rates that otherwise would have been collected during the period between the effective date of the initial order and the effective date of the rates as increased, together with interest as determined by the department at a rate not to exceed the maximum interest rate otherwise allowed by law.
(b) This surcharge shall be assessed over a period equal to the period between the date of the initial order and the effective date of the rates, as increased.
(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 effective date of the rates, as increased.