In Re Marriage of Petersen, 2011 IL 110984

Janet and Kevin Petersen married in 1983 and separated in 1996; dissolution judgment in 1999 awarded custody to Janet and reserved education expenses for future determination.
The 1999 decree ordered Kevin to provide child support, health insurance, life insurance and to name children as irrevocable beneficiaries for their college expenses until support ends.
The parties incorporated a Custody and Visitation Agreement granting Janet final educational decision-making authority while requiring Kevin to be consulted.
In 2007 Janet petitioned to allocate college expenses for Gregory (Cornell, class of 2006) and Ian (Wake Forest to UT transfer) and to address Ellis (Cal Poly, admitted fall 2007).
Circuit court awarded Kevin 75% of total college expenses, totaling $227,260.68 for past expenses and $46,290.91 for 2008-09 Ian/Ellis expenses; appellate court partial affirmance/reversal.
Illinois Supreme Court reviewed whether Section 510 MDAs (modifications) apply to reserved college-expense issues and whether modification is retroactive; court reversed and remanded to recalculate under 750 ILCS 5/513 with considerations of both parents’ resources.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Section 510 applies to reserved college expenses.	Petersen argues Section 510 does not apply to education expenses under Section 513.	Petersen argues Section 510 applies because reserved issues become modifications.	Section 510 applies; reserved college expenses constitute a modification.
Whether the modification can be retroactive to pre-petition expenses.	Janet contends the modification should cover pre-petition expenses if within the decree’s scope.	Kevin contends retroactive modification is barred by Section 510 for pre-petition periods.	Retroactive modification is barred; only post-petition installments may be modified.
Whether the trial court could award a fixed percentage to Kevin for all college expenses.	Requests percentage allocation based on equity and circumstances.	Argues for court-determined equitable allocation under 513.	Remand to recalculate based on all relevant factors under 750 ILCS 5/513.
Whether to remand for recalculation rather than sustain the 75% share.	Seeks continuation of 75% share.	Seeks recalculation under Section 513 factors.	Remanded for recalculation applying 513(b) factors including parental resources.

In re Marriage of Sreenan, 81 Ill.App.3d 1025 (1980) (context of section 513 expenses as child support alongside section 505)
In re Marriage of Coram, 86 Ill.App.3d 845 (1980) (section 513 expenses treated as support alongside 505)
In re Marriage of Waller, 339 Ill.App.3d 743 (2003) (education expenses as form of support under 513/505)
Nerini v. Nerini, 140 Ill.App.3d 848 (1986) (reservation of support deemed modification under 510)
Conner v. Watkins, 158 Ill.App.3d 759 (1987) (reservation of custody/support treated as modification under 510)
Sommer v. Borovic, 69 Ill.2d 220 (1977) (retention of jurisdiction to enforce and modify for child custody/relief)
In re Marriage of Henry, 156 Ill.2d 541 (1993) (retroactive modification limits; 510(a) interpretation)