Whenever there is no money in the hands of the treasurer of any school district to which Sections 32-2 to 32-4.11, inclusive, shall apply, to defray the necessary expenses of such district, including amounts necessary to pay maturing principal and interest of bonds, it is lawful for the school board of the district to draw and issue warrants against and in anticipation of any taxes already levied for the payment of the necessary expenses of the district, either for transportation, educational or for all operations, building and maintenance purposes, or for payments to the Illinois Municipal Retirement Fund, or for the payment of maturing principal and interest of bonds, as the case may be, to the extent of 85% of the total amount of any such taxes levied. The warrants shall show upon their face that they are payable solely from said taxes when collected, and shall be received by any collector of taxes in payment of the taxes against which they are issued. The taxes against which the warrants are drawn shall be set apart and held for their payment. Every warrant shall bear interest, payable only out of the taxes against which it shall be drawn, at a rate not to exceed the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract, if issued before January 1, 1972 and not to exceed the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract, if issued after January 1, 1972, from the date of its issuance until paid, or until notice is given by publication in a newspaper or otherwise that the money for its payment is available and that it will be paid upon presentation.
     With respect to instruments for the payment of money issued under this Section either before, on, or after the effective date of this amendatory Act of 1989, it is and always has been the intention of the General Assembly (i) that the Omnibus Bond Acts are and always have been supplementary grants of power to issue instruments in accordance with the Omnibus Bond Acts, regardless of any provision of this Act that may appear to be or to have been more restrictive than those Acts, (ii) that the provisions of this Section are not a limitation on the supplementary authority granted by the Omnibus Bond Acts, and (iii) that instruments issued under this Section within the supplementary authority granted by the Omnibus Bond Acts are not invalid because of any provision of this Act that may appear to be or to have been more restrictive than those Acts.