If, at any election held prior to March 19, 2004, the voters of a school district having a population of less than 500,000 inhabitants approved the proposition to increase the educational purposes tax rate of the district and the proposition to increase the rate set forth as the existing maximum-authorized educational purposes tax rate of the district the tax rate most recently extended for educational purposes, then, for the purposes of this Code and the Property Tax Code, the maximum-authorized educational purposes tax rate of the district shall be calculated as follows:
Within 10 days after the effective date of this amendatory Act of the 93rd General Assembly, the school board of any school district affected by this subsection (a) may, notwithstanding the requirements of any other law to the contrary, amend its certificate of tax levy for any year for which its equalized assessed valuation has not yet been certified by the county clerk. The amended certificate of tax levy shall be filed with the county clerk within the 10-day period after the effective date of this amendatory Act of the 93rd General Assembly.
105 ILCS 5/17-3.5