(a)(1) On motion of either parent, the Office of Child Support, any other person to whom support has previously been granted, or any person previously charged with support, and upon a showing of a real, substantial and unanticipated change of circumstances, the court may annul, vary, or modify a child support order, whether or not the order is based upon a stipulation or agreement. If the child support order has not been modified by the court for at least three years, the court may waive the requirement of a showing of a real, substantial, and unanticipated change of circumstances.
(2) The Office of Child Support may independently file a motion to modify child support or change payee if providing services under Title IV-D of the Social Security Act, if a party is or will be incarcerated for more than 90 days, if the family has reunited or is living together, if the child is no longer living with the payee, or if a party receives means-tested benefits.
(b) A child support order, including an order in effect prior to adoption of the support guideline, which varies more than ten percent from the amounts required to be paid under the support guideline, shall be considered a real, substantial, and unanticipated change of circumstances.
(c) The following shall be considered a real, substantial, and unanticipated change of circumstances:
(1) Receipt of workers' compensation, disability benefits, or means-tested public assistance benefits.
(2) Unemployment compensation, unless the period of unemployment was considered when the child support order was established.
(3) Incarceration for more than 90 days, unless incarceration is for failure to pay child support.
(d) A motion to modify a support order under subsection (b) or (c) of this section shall be accompanied by an affidavit setting forth calculations demonstrating entitlement to modification and shall be served on other parties and filed with the court. Upon proof of service, and if the calculations demonstrate cause for modification, the magistrate shall enter an order modifying the support award in accordance with the calculations provided, unless within 15 days of service of, or receipt of, the request for modification, either party requests a hearing. The court shall conduct a hearing within 20 days of the request. No order shall be modified without a hearing if one is requested.
(e) An order may be modified only as to future support installments and installments which accrued subsequent to the date of notice of the motion to the other party or parties. The date the motion for modification is filed shall be deemed to be the date of notice to the opposing party or parties.
(f) Upon motion of the court or upon motion of the Office of Child Support, the court may deem arrears judicially unenforceable in cases where there is no longer a duty of support, provided the court finds all of the following:
(1) The obligor is presently unable to pay through no fault of his or her own.
(2) The obligor currently has no known income or has only nominal assets.
(3) There is no reasonable prospect that the obligor will be able to pay in the foreseeable future.
(g) Upon motion of an obligee or the Office of Child Support, the court may set aside a judgment that arrears are judicially unenforceable based on newly discovered evidence or a showing of a real, substantial, and unanticipated change in circumstances, provided the court finds any of the following:
(1) The obligor is presently able to pay.
(2) The obligor has income or has only nominal assets.
(3) There is a reasonable prospect that the obligor will be able to pay in the foreseeable future.