6(1)Regulations may provide—
(a)that provision under paragraph 3 above or provision under paragraph 4 above or provision under neither of them shall apply in the case of an asset or liability according to the circumstances of the case;
(b)that provision under paragraph 3(3)(a) above or provision under paragraph 3(3)(b) above shall apply in the case of an asset or liability according to the circumstances of the case.
(2)The circumstances may be framed by reference to—
(a)whether, and how, exchange differences arising as regards the asset or liability would be taken into account for tax purposes apart from this Chapter;
(b)such other factors as the Treasury think fit;
and for this purpose exchange differences are gains and losses attributable to fluctuations in currency exchange rates.