Cal. Code Regs. tit. 2 § 948
Costs applied are defined as the interdepartmental transfer of materials and services, shown as a credit to the total expenditures of the transferring department.
These adjustments differ from adjustments to individual accounts as follows: There is no reduction of expense in the county group of funds taken as a whole; there is simply a reassignment of cost within that group; they do not represent corrections; the adjustment is not to a specific account, but to a group of accounts.
The costs applied device shall be used only within the general county group of funds. It does not apply to transactions between the county and: (1) private persons or agencies, or (2) cities and other governmental agencies required to file separate reports with the State Controller.
Cal. Code Regs. Tit. 2, § 948