Source: http://rochesterfamilylawyer.korotkinlaw.com/2008/10/20/child-support-in-shared-custody-situations/
Timestamp: 2019-04-18 21:00:19+00:00

Document:
Child support under Domestic Relations Law §240 or Family Court Act §413 is not difficult to calculate in situations where there is a parent who clearly has a primary physical residence of the child. However, where the child spends equal time with both parents, these issues become a lot more complicated. Domestic Relations Law §240[1-b](f) requires that “The court shall calculate the basic child support obligation, and the non-custodial parent’s pro rata share of the basic child support obligation”. Therefore, which parent becomes the non-custodial parent in shared custody situation? This question was addressed in the 1998 case of Baraby v. Baraby, 250 A.D.2d 201 (3rd Dept. 1998).
where, as here, the parents’ custodial arrangement splits the children’s physical custody so that neither can be said to have physical custody of the children for a majority of the time, the parent having the greater pro rata share of the child support obligation, determined after application of the three-step statutory formula of the CSSA, should be identified as the “noncustodial” parent for the purpose of support.
Since the statute is silent as to joint custody arrangements, the court ruled that for purposes of complying with the statute, one parent must be deemed “custodial” and the other “non custodial.” This step must be taken before a deviation from the support guidelines could be made under Domestic Relations Law §240[1-b](f) and (g). The parent with higher income is declared to be the non-custodial parent for child support calculations. This result problematic in situations where the parents’ incomes are close to each other.
For parents who are contemplating true shared custody, the issues of child support must be carefully addressed in the separation agreement to provide language explaining the contemplated child support arrangement and the reasons the parents are entering into such arrangement. Baraby does not stand for the proposition that the parent with the higher income must pay full child support. The parents are still free to opt out of the Child Support Standards Act, provided that at least minimum statutory child support is being paid, and the reasons for the opt-out are clearly stated.
If the court is deciding these issues in the contest of child support modification, then the party with the higher income should present information allowing the court to make a deviation from the child support guidelines pursuant to Domestic Relations Law §240[1-b](f) and (g).

References: §240
 §413
 §240
 v. 
 §240
 §240