(g) FMCS will waive the collection of interest on the debt or any portion of the debt which is paid within 30 days after the date on which interest began to accrue. FMCS may extend this 30-day period, on a case-by-case basis, if it reasonably determines that such action is appropriate. Also, FMCS may waive, in whole or in part, the collection of interest, penalties, and/or administrative costs assessed under this section under the criteria specified in part 103 of the Federal Claims Collection Standards (4 CFR part 103) relating to the compromise of claims (without regard to the amount of the debt), or if the agency determines that collection of these charges would be against equity and good conscience, or not in the best interests of the United States. Waiver under the first sentence of this paragraph (g) is mandatory. Under the second and third sentences, it may be exercised under the following circumstances:

1. (1) Waiver of interest pending consideration of a request for reconsideration, administrative review, or waiver of the underlying debt under a permissive statute, and
2. (2) Waiver of interest where FMCS has accepted an installment plan, there is no indication of fault or lack of good faith on the part of the debtor, and the amount of interest is large enough in relation to the size of the installments that the debtor can reasonably afford to pay, that the debt will never be repaid.