Any bonds issued under the provisions of this Sub-part shall not exceed in principal the amount of the original issue, shall not run for a period longer than the number of years of the original issue, and shall bear a maximum rate of interest not to exceed the rate of such original issue, shall not be sold for less than par, and the proceeds thereof shall not be used for any purpose other than that for which the bonds are issued.
La. R.S. § 33:4322