7. After regulation 5 (date from which a decision revised under section 9 takes effect) there shall be inserted the following regulation—
5A.—(1) Where the date from which a decision took effect is found to be erroneous on a revision under section 16 of the Child Support Act, the revision shall take effect from the date on which the decision revised would have taken effect had the error not been made.
(2) Where the Secretary of State considers it appropriate to revise a decision under section 12(1) of the Child Support Act as if he were revising a decision under section 11 of that Act, the revision shall take effect from the first day of the maintenance period in which the information required to make a maintenance calculation was provided, except where—
(a)the non-resident parent satisfies the Secretary of State—
(i)that he used his best endeavours to obtain the information required by the Secretary of State; and
(ii)the failure to provide the information was not his fault; or
(b)the decision which is treated as being made under section 11 of the Child Support Act is at a higher rate than the rate of liability which had been imposed by the decision made under section 12(1) of that Act.”.