Notwithstanding s. 121.91, if a school district held a referendum before February 5, 2001, to exceed its revenue limit under s. 121.91 (2m), and the resolution adopted by the school board and referred to in the question submitted to the electors specified a mill rate to be used to calculate the revenue limit increase, the amount by which the school district’s revenue limit is increased as a result of the referendum for each year specified in the referendum is the dollar amount agreed to by the department of public instruction and the school board of that school district.