CA Gov't Code Section 50969

The approximate and actual contributions payable by a contracting department shall be similar to premiums under insurance policies. The approximate contribution quoted by the board to the department is subject to the contingency that the actual contribution certified by the board after the approval of a contract may differ from the approximate contribution because of any of the following:

(a)

Time elapsed between the quotation and operative date of the contract.

(b)

Any changes in the facts or assumptions upon which the quotation was based.