The Court could order a step-parent to pay an amount of child support that is different from the Guideline amount if there is also another parent with a legal duty to support that same child.
If each parent has the child at least 40% of the time, the Guidelines do say that there is “shared custody.” In this case, the amount of Guideline child support could be less because it is assumed that both parents are paying for the child’s ordinary expenses. However, the legislation does not tell the Court how to figure out how much time is spent with each parent. Instead, it is up to the parent who claims to have a “shared custody” arrangement to prove that the child is with him or her at least 40% of the time. What matters is the actual time the child spends with each parent, not what a separation agreement or court order says. Importantly, reaching the 40% threshold is not a guarantee that there will be adjustment; rather it simply gives that parent the opportunity to make the argument.
More problematic, the Guidelines do not say how to calculate support in a shared custody situation, so it is often very difficult to know in advance what a Court might decide. Even the case law is confusing. In the event a Court is inclined to make an adjustment, it will first figure out the Guideline amount for each parent based on his and her gross incomes and then subtract the smaller amount from the larger. What is left is commonly called the “set-off” amount. The Court will then consider the additional costs of the shared custody arrangement, including shelter, food and clothing costs. The Court is also entitled to look at the personal situations of each parent, including if they live with someone else with whom they share expenses and or if they have other dependents to support. All of this will go into deciding the appropriate amount of Guideline support.
Sometimes one or more children will live with each parent. In this instance, each parent must pay support to the other according to the Guidelines for any child living with the other parent. The parent who must pay the higher amount will pay the difference to the other parent.