5. For the purposes of regulation 4(1), the Comptroller shall determine —
(a)
the income chargeable to tax at the rate of 10% of an approved headquarters company having regard to such expenses, capital allowances and donations allowable under the Act as are, in his opinion, to be deducted in ascertaining such income; and
(b)
the manner and extent to which any losses arising from the qualifying services and qualifying treasury, investment or financial activities approved under section 43E(2) of the Act may be deducted under the Act in ascertaining the chargeable income of the approved headquarters company.