Cal. Gov. Code § 31870.4
Notwithstanding any other provision of law, the accumulation established in Section 31870, 31870.1, 31870.2, or 31870.3 shall be computed by multiplying the existing accumulation from prior years by an amount equal to one plus the amount of any cost-of-living increase or decrease in the current year, and adding to this result the "accumulation adjustment," where "accumulation adjustment" means the amount of any cost-of-living increase or decrease in the current year that is not met by the maximum annual change in allowances provided in Section 31870, 31870.1, 31870.2, or 31870.3, whichever is applicable. At no time may the accumulation established in Section 31870, 31870.1, 31870.2, or 31870.3 be less than zero.
This section shall not be operative in any county until it is adopted by a majority vote of the board of supervisors. Upon adoption of this section by the board of supervisors, the accumulation of each member under Section 31870, 31870.1, 31870.2, or 31870.3, whichever is applicable, shall be recomputed as if this section had been in effect on the member's date of retirement.
Ca. Gov. Code § 31870.4