Typically, child support payments are fixed amounts (with the exception of COLA adjustments and special modifications) that do not change, regardless of which parent currently has custody of the child.
This is because child support is intended to help pay for the basic living expenses, such as rent, utilities, clothing, insurance and the like, all of which remain the same even when the child is visiting the non-custodial parent.
That said, there are instances where the parties have agreed to vary the amounts during longer visitation periods such as summer break and extended vacations since the day-to-day expenses such as food and entertainment will shift from the custodial parent to the non-custodial parent during these visits.
This is strictly done on a case by case basis and must be approved by the court, either as a part of your original divorce decree or as a later modification of the decree. If you wish to modify your child support agreement in this manner, you should consult your attorney and also talk to your ex-spouse to see if the two of you can come to an agreement regarding the change. You’ll also likely need to show that the visits in question are truly “extended” and not just a few days here and there.
This type of modification must be granted by the court so you’ll need to schedule a new hearing and get the judge to sign off on your amendment. An agreement between you and your ex-spouse alone is not sufficient to allow you to decrease your child support payments, however most judges will grant this type of request when both parties are in agreement.