If a custody order by the court, contains a detailed shared parenting plan which provides that the child will reside no less than one hundred eighty nights per calendar year in each parent's home, and that the parents will share the duties and responsibilities of parenting the child and the expenses of the child in proportion to their incomes, the court may, if deemed appropriate under the circumstances, grant a cross credit on the amount of the child support obligation based on the number of nights the child resides with each parent. The shared parenting child support cross credit shall be calculated as follows:
In deciding whether a shared parenting child support cross credit is appropriate, the court shall consider whether it would have a substantial negative effect on the child's standard of living.
It is presumed that the parenting time is exercised. If the parenting time exercised substantially deviates from the parenting time ordered, either party may petition the court for a modification of the support order without showing any other change in circumstances.
SDCL 25-7-6.27