California Code, Government Code - GOV § 31874

This article (commencing with Section 31870) may be made applicable in any county on the date specified in the ordinance, or if no such date is specified, on the first day of the month after the effective date of an ordinance adopted by the board of supervisors to this effect, provided that an actuarial survey of the retirement system has been made by the adopting county prior to the passage of said ordinance.  No provision of this chapter shall prevent or be construed to prevent the use and expenditure of surplus described in Section 31592.2 to fund any part or all of any increases in allowances otherwise permitted after this article or Article 16.6 (commencing with Section 31875) or both this article and Article 16.6 or any of the provisions of this article or Article 16.6 have been made applicable.

Except in a county of the first class, upon adoption by a county providing increases in allowances pursuant to this article, of Article 5.5 (commencing with Section 31510) of this chapter, only that portion of the increases in allowances which is paid from surplus earnings described in Section 31592.2 shall be paid, instead, from the Supplemental Retiree Benefits Reserve established pursuant to Section 31510.8.