The method of computing and paying the amounts provided for in Sections 18521 and 18522 for each quarter shall be as follows:
(a)
The department shall, prior to the beginning of each quarter, estimate the amount to be paid for such quarter to each county under the provisions of Sections 18521 and 18522, such estimate to be based on a report filed by each county containing (1) its estimate of the total sum to be expended in such quarter in accordance with the provisions of this chapter; (2) records showing the number of individuals (cases) estimated to be in need of relief during the ensuing quarter; and (3) such other information and investigation as the department may find necessary.
(b)
The department shall then certify to the State Controller the amounts so estimated by it for each county, reduced or increased as the case may be, by any sum by which it finds that its estimate for any prior quarter was greater or less than the amount which should have been paid to the county under this chapter for such quarter.
(c)
The State Controller shall thereupon draw the necessary warrants, and prior to audit or settlement by the department and the State Controller, the State Treasurer shall pay to the treasurer of each county the amount so certified.
Upon the order of the department, the amount approved for the quarter may be paid in monthly installments and, if paid in monthly installments, all necessary adjustments for the prior quarters shall be made by additions or deductions from the allowance for the first month of each new quarter or in the manner prescribed by the department.