Gov. Code, § 31491.2

(a) Notwithstanding Section 31491, any retired member receiving a retirement pension may present evidence in the form required by the board of the retired member’s federal estimated primary insurance amount provided that the retired member is not receiving a federal primary insurance amount. For the purposes of this section, the federal estimated primary insurance amount shall be the amount payable under the federal system as of the retired member’s normal federal retirement age. Should the federal estimated primary insurance amount equal zero, the retired member shall not have his or her pension benefit reduced for an estimated primary insurance amount as required in subdivision (e) of Section 31491.

(b) Following receipt of that evidence, the board shall adjust the retired member’s pension to equal the amount of the pension to which he or she would have been entitled on that date had the estimated primary insurance amount calculated in Section 31491 equaled zero.

(c) The adjustment calculated in subdivision (a) shall be applied to the retired member’s pension beginning in the month upon which the retired member presents evidence required by the board.

(d) Notwithstanding subdivision (a), upon attaining federal retirement age, the retired member shall submit any evidence as may be required by the board of the retired members’ federal estimated or actual primary insurance amount. Following receipt of that evidence, the board shall adjust the retired member’s pension in accordance with subdivision (j) of Section 31491.

(e) This section shall not be operative in any county until the board of supervisors, by resolution adopted by majority vote, makes this section applicable.