(1) On behalf of the Commonwealth, the Secretary may waive the Commonwealth's right to recover the whole or a part of a debt from a debtor only in the circumstances described in section 97, 98, 99, 100, 101 or 102.
(2) A waiver takes effect:
(a) on the day specified in the waiver (whether that day is before, after or on the day on which the decision to waive is made); or
(b) if the waiver does not specify when it takes effect--on the day on which the decision to waive is made.