Except as to applications for refund or waiver of freight charges under § 502.271 and claims which are settled by agreement of the parties, and absent fraud or misconduct of a party, interest granted on awards of reparation in complaint proceedings instituted under the Shipping Act of 1984 will accrue from the date of injury to the date specified in the Commission order awarding reparation. Compounding will be daily from the date of injury to the date specified in the Commission order awarding reparation. Normally, the date specified within which payment must be made will be fifteen (15) days subsequent to the date of service of the Commission order. Interest shall be computed on the basis of the average monthly secondary market rate on six-month U.S. Treasury bills commencing with the rate for the month that the injury occurred and concluding with the latest available monthly U.S. Treasury bill rate at the date of the Commission order awarding reparation. The monthly secondary market rates on six-month U.S. Treasury bills for the reparation period will be summed up and divided by the number of months for which interest rates are available in the reparation period to determine the average interest rate applicable during the period. [Rule 253.]