The court may retain jurisdiction over the case for such period of time as is necessary for the successful implementation of the plan.

Except as provided in subsection (a) of this section, the court shall close the case when administration of the case has been completed.

(Pub. L. 95–598, Nov. 6, 1978, 92 Stat. 2625; Pub. L. 98–353, title III, § 498, July 10, 1984, 98 Stat. 384.)