9(1)This paragraph applies where—
(a)the taxpayer makes or amends a claim for relief under any other provision of the Income Tax Acts for either of the years to which an averaging claim relates, and
(b)the making or amendment of the claim would be out of time but for paragraph 8.
(2)The claim or amendment is given effect in the later year.
(3)In so far as the claim or amendment relates to income of the earlier year, the amount claimed, or (as the case may be) the increase or reduction in the amount claimed, shall be equal to the difference between—
(a)the amount in which the taxpayer is chargeable to tax for the earlier year (“amount A”), and
(b)the amount in which he would be so chargeable on the assumption that effect could be, and was, given to the claim or amendment in relation to that year (“amount B”).
(4)That claim or amendment is given effect in the later year by increasing the amount referred to in section 59B(1)(b) of the Management Act (aggregate amount of payments on account made by the taxpayer) or, as the case may require, by increasing the amount of tax payable.
(5)Where effect falls to be given to two or more associated claims, amounts A and B above shall each be determined on the assumption that effect could have been, and had been, given to the other claim or claims in relation to the earlier year.
(6)In this paragraph “amend” includes revoke and “amendment” has a corresponding meaning.