A support order can offset the payments for one kind of support against payments going the opposite way for another kind of support, the Court of Appeals says in O'Reilly v. O'Reilly (5/31/16), unpublished. Thus, when ordering a father to pay alimony to the mother, and the mother to pay child support to him, a court can order him to pay the net difference rather than having money going in both directions.
Nor was it error for a judge to order children's non-covered medical expenses shared in proportion to income, even though there was no discussion of that during the trial. All support orders are required to address this by Code Section 20–108.2 D, and the order followed the by-default formula for doing so.
The mother believed, as some parents do after looking at the support guideline spreadsheets, that the father was supposed to pay her the amount listed as "father's obligation" even though he was the custodial parent. The Court disagreed, and said that that amount is what he's assumed, but not ordered, to spend on the children from his own income, in addition to the child support the mother pays him.