Section 66.23 - Interim recalculation of penalty(a) The Administrator, upon concluding that a previously approved penalty calculation no longer is accurate, may:(1) Request, in writing, that the source owner or operator submit a revised calculation in the form specified in § 66.13(a) . The Administrator shall respond to any information submitted in accordance with the provisions of § 66.51 .(2) Notify the source owner or operator, in writing, that the penalty has been recalculated based upon information in the Administrator's possession. The source owner or operator shall respond as provided in § 66.52 .(b) If a source owner or operator believes that, because of changed circumstances, a penalty calculation which has been accepted by EPA no longer is accurate, he may submit a revised penalty calculation and schedule to the Administrator. The revised calculation shall be in the form specified in § 66.13(a)(1) . The Administrator shall respond in accordance with the provisions of § 66.51 . The decision to accept the interim calculation or to grant a hearing on this issue shall be solely within the discretion of the Administrator.