The superintendent shall include the education centers program in the biennial budget request. Contracts between the superintendent of public instruction and the education centers shall include quarterly plans which provide for relatively stable student enrollment but take into consideration anticipated seasonal variations in enrollment in the individual centers. Funds which are not expended by a center during the quarter for which they were planned may be carried forward to subsequent quarters of the fiscal year. The superintendent shall make payments to the centers on a monthly basis pursuant to RCW
28A.205.040.