(a) In this section -
"trade", "income from the sale of goods", "charges on income paid for the purposes of the sale of goods" and "the sale of goods and merchandise" have the same meanings respectively as in section 454;
"a loss from the sale of goods" has the same meaning as in section 455;
"an excess of charges on income paid for the purpose of the sale of goods" in the course of the trade in an accounting period shall be so much of an amount, being the amount by which the charges on income paid by a company for the purpose of the sale of goods in the course of the trade in that period exceed the income from the sale of goods in the course of the trade in that period, as does not exceed the excess referred to in section 420(6) as computed for the company for that period.
(b) Section 454(1)(b) shall apply for the purposes of this section as it applies for the purposes of section 454.
(2) Notwithstanding subsections (1) and (6) of section 420 and sections 420A(3) and 421, whe