(1) Section 485G of the Principal Act is amended by inserting the following subsections after subsection (3):

 "(4)

(a) Subject to paragraph (b) and subsection (5), where under any provision of the Tax Acts (other than any provision of this Chapter) the calculation of a relief, deduction, credit in relation to tax or, as the case may be, a reduction in the amount of tax payable arises for a tax year which requires total income, taxable income, tax payable or tax chargeable for the year to be taken into account as part of the calculation -

(i) that calculation shall be carried out as if this Chapter, other than section 485F, does not apply, and

(ii)

(I) in the case of a relief or deduction, effect shall be given to such relief or deduction before the application of this Chapter but after the application of section 485F, or

(II) in the case of a credit in relation to tax or, as the case may be, a reduction in the amount of tax payable, the benefit of that credit or reduction (as calculated in accordance with subparagraph (i)) shall be given against the amount of tax to be charged on the individual for the year involved in relation to his or her taxable income as determined in accordance with section 485E.