HSC § 25206.4

The department shall establish rates for indirect costs that are specific to each program and shall review and update the indirect cost rates based upon increases or decreases in the amounts of grants received by the department, department reorganizations, and other relevant factors, but not less than once every six months, based upon the previous 12 months of expenditure data. The department shall apply the indirect cost rates prospectively and shall not make retroactive adjustments in those rates.