119.This section amends section 17 of the 1991 Act to clarify the decisions which may be superseded.
120.Subsections (1) and (2) amend section 17(1) to provide for the supersession of:
	a reduced benefit decision;
	a decision of an appeal tribunal on a variation referral; and
	a decision of a Commissioner on an appeal from a decision referred to in paragraph (b) or (d) (a decision of an appeal tribunal, including a decision on referral of a variation).
121.Subsection (3) substitutes subsection (4) of section 17 of the 1991 Act with two new subsections (4) and (4A) which provide for the date from which a supersession takes effect. The existing section 17 provides that a supersession takes effect from the date of the decision or the date of the application unless otherwise prescribed. Regulations have been made which enable decisions to take effect from the date of the change of circumstances which leads to the supersession (the Child Support (Miscellaneous Amendments) (No. 2) Regulations 1999 (SI 1999/1047)).
122.In child support, decisions normally take effect from the beginning of a maintenance period: this subsection amends section 17 to provide for this. A “maintenance period” represents the weekly unit in which maintenance liability is calculated. The first maintenance period starts on the date that the non‑resident parent's liability begins: each subsequent maintenance period starts on the day after the last day of the previous one. Other periods may be prescribed for particular cases.
Part 1: Child Support. Commentary on Sections Part II: Regulatory controls Section 9: Decisions superseding earlier decisions