657. Shared or split physical custody
(a) When each parent exercises physical custody for 30 percent or more of a calendar year, the total child support obligation shall be increased by 50 percent to reflect the additional costs of maintaining two households. Each parental support obligation shall be determined by dividing the total support obligation between the parents in proportion to their respective available incomes and in proportion to the amount of time each parent exercises physical custody. The parental support obligations shall then be offset, with the parent owing the larger amount being required to pay the difference between the two amounts to the other parent.
(b) When one parent exercises physical custody for 25 percent or more but less than 30 percent of a calendar year, each parent's respective share of the total support obligation shall be determined in accordance with a shared costs table adopted by the agency of human services by rule. The shared costs table shall be developed in such a way as to minimize economic disputes over parent-child contact or visitation and shall reflect the additional costs of maintaining two households by increasing the total support obligation by 50 percent.
(c) In no event shall a parent be required to pay child support under subsection (a) or (b) of this section in an amount greater than the amount that would have been ordered under the support guidelines.
(d) For purposes of this section, “physical custody” means keeping the children overnight. The parent having custody for the greater period of time shall be considered the custodial parent for the purposes of section 661 of this title.
(e) When each parent has physical custody of at least one of the children, a theoretical support payment shall be determined for each parent for the children in the custody of the other, prorating the obligations among all children in the household. The obligations shall then be offset, with the parent owing the larger amount being required to pay the difference between the two amounts to the other parent.