All moneys paid pursuant to such agreement shall be paid into the county treasury and be credited to the drain fund of such drain. In the discretion of the board of drain commissioners, the amount received in payment of proportionate share of original cost of such drain which will not be required for future maintenance of the drain may be paid out to the owners of record, at the time of such payment, of land which was assessed for such drain. Applications for such payments shall be made in the form prescribed by the board of drain commissioners and payments shall be made by the execution and delivery of drain board warrants drawn on the drain fund. The payment to the owner or owners of each tract of land shall be a percentage of the total payment to be made to all the owners equal to the percentage of the cost of the drain which was assessed against such tract of land.