105 ILCS 5/2-3.33
To recompute within 3 years from the final date for filing of a claim any claim for general State aid reimbursement to any school district and to recompute and adjust any such claims within 6 years from the final date for filing when there has been an adverse court or administrative agency decision on the merits affecting the tax revenues of the school district. However, no such adjustment shall be made regarding equalized assessed valuation unless the district's equalized assessed valuation is changed by greater than $250,000 or 2%. Any adjustments for claims recomputed for the 2016-2017 school year and prior school years shall be applied to the apportionment of evidence-based funding in Section 18-8.15 of this Code beginning in the 2017-2018 school year and thereafter. However, the recomputation of a claim for evidence-based funding for a school district shall not require the recomputation of claims for all districts, and the State Board of Education shall only make recomputations of evidence-based funding for those districts where an adjustment is required. The State Board is authorized to and shall apply corrections to data used in evidence-based funding calculations that may result in current year adjustments and shall recover funds previously scheduled to be distributed or previously distributed to an Organizational Unit or specially funded unit during a fiscal year in accordance with Section 18-8.15 of this Code.
Except in the case of an adverse court or administrative agency decision, no recomputation of a State aid claim shall be made pursuant to this Section as a result of a reduction in the assessed valuation of a school district from the assessed valuation of the district reported to the State Board of Education by the Department of Revenue under Section 18-8.05 or 18-8.15 of this Code unless the requirements of Section 16-15 of the Property Tax Code and Section 2-3.84 of this Code are complied with in all respects.
This paragraph applies to all requests for recomputation of a general State aid or evidence-based funding claim received after June 30, 2003. In recomputing a general State aid or evidence-based funding claim that was originally calculated using an extension limitation equalized assessed valuation under paragraph (3) of subsection (G) of Section 18-8.05 of this Code or Section 18-8.15 of this Code, a qualifying reduction in equalized assessed valuation shall be deducted from the extension limitation equalized assessed valuation that was used in calculating the original claim.
From the total amount of general State aid or evidence-based funding to be provided to districts, adjustments as a result of recomputation under this Section together with adjustments under Section 2-3.84 must not exceed $25 million, in the aggregate for all districts under both Sections combined, of the general State aid or evidence-based funding appropriation in any fiscal year; if necessary, amounts shall be prorated among districts. If it is necessary to prorate claims under this paragraph, then that portion of each prorated claim that is approved but not paid in the current fiscal year may be resubmitted as a valid claim in the following fiscal year.
105 ILCS 5/2-3.33