23.—(1) This regulation applies where the non-resident parent’s gross weekly income is based on an amount of current income by virtue of regulation 34(2) and, before the next review date, there is a change of circumstances affecting the amount of that current income.
(2) No supersession decision giving effect to that change may be made unless the amount of that current income has changed by at least 25%.
(3) Paragraph (1) does not prevent a supersession decision that—
(a)is made on the Secretary of State’s own initiative under regulation 20 (updating weekly income at the annual review) or regulation 22 (periodic check where current income unchanged for 11 months);
(b)is made on the ground mentioned in regulation 17(1)(c) (error of law); or
(c)supersedes a decision determining the non-resident parent’s gross weekly income on the basis of regulation 42 (estimate of current income where insufficient information available).
(4) Where the condition in paragraph (2) is satisfied, the current income (as changed) is to apply even if it does not differ from historic income by an amount that is at least 25% of historic income.