(a) Allowance.--Upon appeal by an affected member, beneficiary or survivor annuitant, the board may waive an adjustment or any portion of an adjustment made under section 8534(b) (relating to fraud and adjustment of errors) if in the opinion of the board or the board's designated representative:

(b) Time period.--In order to obtain consideration of a waiver under this section, the affected member, beneficiary or survivor annuitant must appeal to the board in writing within 30 days after receipt of notice that benefits have been adjusted or, if no notice was given, within 30 days after the adjustment was known or should have been known to the affected member, beneficiary or survivor annuitant. For any adjustments made prior to the effective date of this subsection for which the member, beneficiary or survivor annuitant appealed to the board and was denied, an appeal under this section must be filed within 90 days of the effective date of this subsection.