IS the kid getting food/clothes/shelter/medical? If so, I don't care how the money coming in from dad/mom is spent by the other party - just as long as whoever is spending it provides those things for the child. At the end of the day non-custodial parent's money going to custodial parents money is going into one fund - the one for the custodial parent. If they are providing, does it matter exactly where that money came from?
But maybe I'm just completely missing something here.