(a) it is necessary, for the purposes of this Part, to work out an amount or value of a fringe benefit; and
(b) the amount or value of the benefit is expressed in a foreign currency;
the amount or value in Australian currency is to be worked out using the market exchange rate for 1 July in the appropriate tax year.
(2) If there is no market exchange rate for 1 July in the appropriate tax year (for example, because of a national public holiday), the market exchange rate to be used is the market exchange rate that applied on the last working day immediately before that 1 July.
(3) For the purposes of this section, the market exchange rate of a foreign currency is the on-demand airmail buying rate for that currency available at the Commonwealth Bank of Australia.