The board of supervisors of any county in which the director is required by Section 2125 to perform the duties of commissioner shall, upon claim which is duly submitted, reimburse the department for all expenses which are incurred by the director in fulfilling his responsibilities in performing such duties. The amount of reimbursement shall not, however, be in excess of an amount which is established by an agreement between the board of supervisors and the director pursuant to Section 482 of this code or Section 25801 of the Government Code.