4(1)This paragraph applies to old expenditure—
(a)in respect of which allowances were made under the old code of allowances, and
(b)in respect of which there is no outstanding balance on the relevant day.
(2)Where this paragraph applies, the new code of allowances shall have effect as if—
(a)the whole of the old expenditure had been incurred on the relevant day; and
(b)under the appropriate provisions of the new code of allowances there had been made allowances equal to that expenditure;
and the provisions of the new code about disposal receipts shall have effect accordingly in relation to events happening on or after the relevant day.