or leases where royalty payments are not received by the Secretary on the date that such payments are due, the Secretary shall charge interest on such underpayments at the same interest rate as the rate applicable under section 6621(a)(2) of the Internal Revenue Code of 1986. (B) Computation In the case of an underpayment, interest shall be computed and charged only on the amount of the deficiency and not on the total amount. (2) Underreporting If there is any underreporting of royalty owed on production from a claim or lease for any production month by any person liable for royalty payments under this section, the Secretary shall assess a penalty of not more than 25 percent of the amount of the underreporting. (3) Self-reporting The Secretary may waive or reduce the assessment under paragraph (2) if the person liable for royalty payments under this section corrects the underreporting before the later of— (A) the date such person receives notice from the Secretary that an underreporting may have occurred