(a) The court may modify a child support order, for the benefit of the child, when a motion is made that alleges a change in the circumstances of a parent or another proper person or persons. A motion for modification of a child support order may be brought by a custodial parent or any other lawful custodian or guardian of the child, by a parent or other person obligated to pay child support for the child or by the Bureau for Child Support Enforcement of the Department of Health and Human Resources of this state.

(b) The provisions of the order may be modified if there is a substantial change in circumstances. If application of the guideline would result in a new order that is more than fifteen percent different, then the circumstances are considered a substantial change.

(c) An order that modifies the amount of child support to be paid shall conform to the support guidelines set forth in section one hundred one, article thirteen, et seq., of this chapter unless the court disregards the guidelines or adjusts the award as provided in section seven hundred two of said article.

(d) The Supreme Court of Appeals shall make available to the courts a standard form for a petition for modification of an order for support, which form will allege that the existing order should be altered or revised because of a loss or change of employment or other substantial change affecting income or that the amount of support required to be aid is not within fifteen percent of the child support guidelines. The clerk of the circuit court and the secretary-clerk of the family court shall make the forms available to persons desiring to represent themselves in filing a motion for modification of the support award.

(e) Upon entry of an order modifying a child support amount the court shall, no later than five days from entry of the order, provide a copy of the modified order to the Bureau for Child Support Enforcement. If an overpayment to one of the parties occurs as a result of the modified terms of the order, funds properly withheld by the Bureau for Child Support Enforcement pursuant the terms of the original order shall not be returned until such time as the Bureau for Child Support Enforcement receives repayment from the party in possession of the overpayment.