California Code, Government Code - GOV § 31678.2

(a) Notwithstanding Section 31678 or any other provision of this chapter, a board of supervisors or a governing body of a district may, by resolution adopted by majority vote, make any section of this chapter prescribing a formula for calculation of retirement benefits applicable to service credit earned on and after the date specified in the resolution, which date may be earlier than the date the resolution is adopted.

(b) A resolution adopted pursuant to this section may, if approved in a memorandum of understanding executed by the board of supervisors and the employee representatives, require members to pay all or part of the contributions by a member or employer, or both, that would have been required if the section or sections specified in subdivision (a), as adopted by the board or governing body, had been in effect during the period of time designated in the resolution.  The payment by a member shall become part of the accumulated contributions of the member.

(c) This section shall only be applicable to members who retire on or after the effective date of the resolution described in subdivision (a).

(d) On or after January 1, 2013, this section is inoperative pursuant to Section 7522.44.