21.4.21. For the purpose of computing a taxpayer’s income for a particular taxation year that is a functional currency year or a reversionary year of the taxpayer, foreign accrual property income of a foreign affiliate of the taxpayer, in respect of the taxpayer for the particular taxation year, is to be determined in accordance with the regulations made under section 579 after taking into account the application of subsection 6.1 of section 261 of the Income Tax Act (R.S.C. 1985, c. 1 (5th Suppl.)) in respect of the taxpayer for the particular taxation year.