SECTION 6.12. Term of Bonds Not To Exceed Life of Improvements.
   Be it further enacted, That the longest term of any serial bond issued under this Act shall not exceed the probable life of the project or purpose for which issued, but an erroneous estimate of the probable life shall in no way affect the validity of the bonds. When two or more projects are financed by one bond issue, the probable life shall be the average estimated life of the projects.