Any rate submitted to the FERC for confirmation and approval on a final basis shall be accompanied with such supporting data, studies, and documents as the FERC may require, and also with the transcripts of forums, written answers to questions, written comments, the Administrator's certification, and the statement of principal factors leading to the decision. The FERC shall also be furnished a listing of those customers and other participants in the rate proceeding who have requested they be informed of FERC action concerning the rates.

If the FERC confirms and approves Provisional Rates on a final basis, such confirmation and approval shall be effective as of the date such rates were placed in effect by the Deputy Secretary, as such date may have been adjusted by the Administrator. If the FERC confirms and approves on a final basis rates submitted by the Administrator without interim approval, such confirmation and approval shall be effective on a date set by the FERC.

If the FERC disapproves Provisional Rates or other submitted rates, the Administrator shall develop Substitute Rates which take into consideration the reasons given by the FERC for its disapproval. If, in the Administrator's judgment, public comment should be invited upon proposed Substitute Rates, the Administrator may provide for a public consultation and comment period before submitting the Substitute Rates. Whether or not such public consultation and comment periods are provided, the Administrator will, upon request, provide customers of the power system and other interested persons with copies of the principal documents used in the development of the Substitute Rates. Within 120 days of the date of FERC disapproval of submitted rates, including Substitute Rates, or such additional time periods as the FERC may provide, the Administrator will submit the Substitute Rates to the FERC. A statement explaining the Administrator's decision shall accompany the submission.

A Provisional Rate that is disapproved by the FERC shall remain in effect until higher or lower rates are confirmed and approved by the FERC on a final basis or are superseded by other rates placed into effect by the Deputy Secretary on an interim basis: Provided, That if the Administrator does not file a Substitute Rate within 120 days of the disapproval or such greater time as the FERC may provide, and if the rate has been disapproved because the FERC determined that it would result in total revenues in excess of those required by law, the rate last previously confirmed and approved on a final basis will become effective on a date and for a period determined by the FERC and revenues collected in excess of such rate during such period will be refunded in accordance with paragraph (g) of this section.

If a Substitute Rate confirmed and approved on a final basis by the FERC is higher than the provisional rate which was disapproved, the Substitute Rate shall become effective on a subsequent date set by the FERC, unless a subsequent Provisional Rate even higher than the Substitute Rate has been put into effect. FERC confirmation and approval of the higher Substitute Rate shall constitute final confirmation and approval of the lower disapproved Provisional Rate during the interim period that it was in effect.

If a Substitute Rate confirmed and approved by the FERC on a final basis is lower than the disapproved provisional rate, such lower rate shall be effective as of the date the higher disapproved rate was placed in effect.

Any overpayment shall be refunded with interest unless the FERC determines that the administrative cost of a refund would exceed the amount to be refunded, in which case no refund will be required. The interest rate applicable to any refund will be determined by the FERC.

A rate confirmed and approved by the FERC on a final basis shall remain in effect for such period or periods as the FERC may provide or until a different rate is confirmed, approved and placed in effect on an interim or final basis: Provided, That the Deputy Secretary may extend a rate on an interim basis beyond the period specified by the FERC.