For the purpose of building or repairing schoolhouses or purchasing or improving school sites, the directors of any school district, when authorized by a majority of the votes cast on such proposition conducted in accordance with the general election law, may borrow money; and, as evidence of such indebtedness, may issue bonds signed by the president and clerk of the board, in denominations of not less than $100, and bearing interest at a rate not exceeding the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract.
     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.
     The proceeds of any bonds issued under authorization of this Section shall be deposited and accounted for separately within the Site and Construction/Capital Improvements Fund.