(a) Except as otherwise provided in Code Section 15-11-602, an order of disposition committing a child adjudicated for a delinquent act to DJJ shall continue in force for two years or until such child is sooner discharged by DJJ. The court which made the order may extend its duration for a period not to exceed two years subject to like discharge, if:

(1) A hearing is held upon DJJ's motion prior to the expiration of the order;

(2) Reasonable notice of the factual basis of the motion and of the hearing and an opportunity to be heard are given to such child and his or her parent, guardian, or legal custodian; and

(3) The court finds that the extension is necessary for the treatment or rehabilitation of such child.

(b) Any other order of disposition except an order of restitution as allowed by paragraph (7) or (8) of subsection (a) of Code Section 15-11-601 shall continue in force for not more than two years. An order of extension may be made if:

(1) A hearing is held prior to the expiration of the order on the court's own motion or upon motion of DJJ or the prosecuting attorney;

(2) Reasonable notice of the factual basis of the motion and of the hearing and opportunity to be heard are given to the parties affected;

(3) The court finds that the extension is necessary to accomplish the purposes of the order extended; and

(4) The extension does not exceed two years from the expiration of the prior order.

(c) The court may terminate an order of disposition or an extension of such a disposition order prior to its expiration, on its own motion or an application of a party, if it appears to the court that the purposes of the order have been accomplished.

(d) Except as otherwise provided in paragraph (7) of subsection (a) of Code Section 15-11-601 and Code Section 17-14-5, when a child reaches 21 years of age, all orders affecting him or her then in force terminate and he or she is discharged from further obligation or control.