Cal. Gov. Code § 31676.97
In every county coming under the provisions of Section 31676.1 subsequent to January 1, 1964, and prior to October 1, 1964, every current service pension and prior service pension payable for time commencing October 1, 1965, is hereby increased to the amount it would be if the provisions of this chapter, including Sections 31676.1 and 31760.1, as they existed on the date that Section 31676.1 became applicable to the members' retirement system, had been in effect on the date of the actual retirement of the member; but this section does not authorize any decrease in any such pension, nor does this section give any such retired member, or his successors in interest, any claim against the county or district for any increase in any pension paid or payable for time prior to October 1, 1965. Calculations of pensions under this section shall be made on the basis of current interest rate and mortality tables.
Ca. Gov. Code § 31676.97