The moneys in the several funds of the district shall be paid out by the county treasurer only upon warrants drawn by the county auditor against the appropriate district fund. The county auditor shall draw warrants against the memorial district bond retirement fund, if that fund contains sufficient moneys, and if not, then, against any other funds of the district in payment of all valid and outstanding bonds of the district at maturity and of interest coupons thereon when due, upon presentation to the county auditor of the bonds or coupons by the owners thereof.