(a) Within thirty days after receipt of a penalty calculation provided pursuant to § 66.13(a)(1) or § 66.43, the Administrator shall notify the source owner or operator in writing, that:

(1) The penalty is provisionally accepted as calculated, subject to any recalculation that may be necessary under § 66.72 after the source has achieved compliance; or

(2) The penalty is incorrect and has been recalculated based on the data provided by the source owner or operator, or other data. The Administrator shall provide a brief statement of the basis for the recalculation and shall identify when and where any supporting data may be examined. The Administrator shall also notify the source owner or operator of the right to petition for a hearing under § 66.52; or

(3) The source owner or operator has not submitted any calculation, or the information submitted is inadequate to enable EPA to verify the owner or operator's penalty calculation. The Administrator shall specify what deficiencies exist and request the source owner or operator to supplement his submission within thirty days of receipt of that request. If an inadequate supplemental submission is made within this time, EPA may calculate the penalty itself or as provided in § 66.22.

(b) Supplemental material provided pursuant to paragraph (a)(3) of this section shall be evaluated as provided in paragraph (a).