The provisions of subparagraph (a)(2)(A) shall apply only in cases in which a party is receiving child support enforcement services from the Department of Healthcare and Family Services under Article X of the Illinois Public Aid Code, and only when at least 36 months have elapsed since the order for child support was entered or last modified.
The court may grant a petition for modification that seeks to apply the changes made to subsection (a) of Section 505 by Public Act 99-764 to an order entered before the effective date of Public Act 99-764 only upon a finding of a substantial change in circumstances that warrants application of the changes. The enactment of Public Act 99-764 itself does not constitute a substantial change in circumstances warranting a modification.
750 ILCS 5/510