The agency requesting a petty cash account or an increase in the amount of petty cash advanced under the provisions of this chapter shall submit its request to the director of financial management in the form and detail prescribed by him or her. The agency's written request and the approval authorized by this chapter shall be the only documentation or certification required as a condition precedent to the issuance of such warrant. A copy of his or her approval shall be forwarded by the director of financial management to the state treasurer.