Except with respect to debts referenced in 31 U.S.C. 3717(g), the Board will charge interest, costs, and a six percent penalty on debts covered by this regulation in accordance with 31 CFR 901.9. The Board will not impose interest charges on the portion of the debt that is paid within 30 days after the date on which interest began to accrue, nor impose penalty charges on the portion of the debt that is paid within 90 days after the date on which penalty began to accrue. The Board will not impose any charges during periods during which collection activity has been suspended pending any review provided for in this part if the reviewing official determines that collection of such charges is against equity and good conscience or is not in the best interest of the United States. The Board may, in its discretion, also waive interest, penalties, and cost charges for good cause shown by the debtor (for example, the debtor is unable to pay any significant portion of the debt within a reasonable period of time, or collection of these charges will jeopardize collection of the principal of the debt) or otherwise as authorized in 31 CFR 901.9(g) and 902.2.