The proceeds of bonds issued under this chapter shall be paid into a special fund or funds in banks qualified to act as depositories in such regional area, county or city, and may be deposited, invested, and disbursed as set out in the agreements relating to such approved project. The proceeds of such bonds shall be used solely for the purposes for which they were issued, interim investments, and the redeeming of any outstanding bonds, and shall be disbursed upon order of the governing body or bodies with such restriction, if any, as the resolution or resolutions authorizing the issuance of the bonds may provide.

If the proceeds of such bonds, by error of calculation or otherwise, shall be less than the cost of the purpose for which they were issued, and the redeeming of any outstanding bonds, unless otherwise provided in the resolution or resolutions authorizing the issuance of such bonds, additional bonds may in like manner be issued to provide the amount of such deficit which, unless otherwise provided in the resolution or resolutions authorizing the issuance of bonds, shall be deemed to be of the same issue and shall be entitled to payment from the same funds without preference or priority of the bonds first issued for the same purpose. However, such additional bonds issued shall not exceed ten percent (10%) of the amount of the original issue.

If the proceeds of the bonds of any issue shall exceed the amount required for the purpose for which the bonds were issued, the surplus shall be paid into the fund established for the payment of the principal of and the interest on such bonds.