(a) Proposed tariff publications. A proposed tariff publication which is not yet effective may be withdrawn at any time by filing a notice with the Commission with a certification that all subscribers have been notified by copy of such withdrawal.

(b) Tariff publications that are subject to investigation. A tariff publication that has been permitted to become effective subject to investigation may be withdrawn at any time by filing a notice with the Commission, which includes a transmittal letter, a certification that all subscribers have been notified of the withdrawal, and the previous tariff provisions that are to be reinstated upon withdrawal of the tariff publication under investigation. Such withdrawal shall be effective immediately upon the submission of the notice, unless a specific effective date is set forth in the notice, and must have the following effects:

(1) Any proceeding with respect to such tariff publication shall be terminated;

(2) The previous tariff rate shall be reinstated; and

(3) Any amounts collected under the withdrawn tariff publication which are in excess of the previous tariff rate shall be refunded within 30 days of the withdrawal with interest as calculated by § 340.1 of this chapter.

(c) Numbering and notating tariff publications. The FERC Tariff number assigned to a tariff publication which has been withdrawn may not be used again.