In the case of any member or member’s beneficiaries whose annual benefit otherwise payable under the provisions of this part has been reduced for any year by reason of application of the 100 percent of compensation limitation on benefits under Section 415(b)(1)(B) of the Internal Revenue Code of 1986 (26 U.S.C. Sec. 415(b)(1)(B)) the reduced annual benefit shall be restored to its full amount otherwise payable for that year. In the case of restorations in respect of annual benefits that were paid prior to January 1, 2000, the additional benefit amount shall be paid by the system to the member or the member’s beneficiaries on or before April 1, 2000.