21.4.17. The following rules apply in computing the Québec tax results of a taxpayer for a taxation year:(a) subject to this chapter, other than this section, Canadian currency is to be used; and
(b) subject to this chapter, other than this section, section 484.6, subparagraph l of the first paragraph of section 485.3 and paragraph b of section 851.22.39, if a particular amount that is relevant in computing those Québec tax results is expressed in a currency other than Canadian currency, the particular amount, other than an amount provided for in subparagraph b or c of the second paragraph of section 1029.8.36.0.95 or 1029.8.36.0.105, is to be converted to an amount expressed in Canadian currency using the relevant spot rate for the day on which the particular amount arose.