This Chapter shall apply to an individual for a tax year where -
(a) the individual's adjusted income for the tax year is equal to or greater than the the income threshold amount, and
(b) the aggregate of the specified reliefs used by the individual in respect of the tax year is equal to or greater than the relief threshold amount,
but this Chapter, other than section 485F, shall not apply for the tax year where 20 per cent of the individual's adjusted income for the tax year is equal to or greater than the aggregate of the specified reliefs used by the individual in respect of the tax year.