The interest imputation rule in s. 80.4(1) trumps the general employee benefit rule in s. 6(1)(a)

Charging interest on credit card balances of bank employees at a lower rates than for regular card holders but at higher than the prescribed rate (currently 2%) does not result in a taxable benefit.  CRA considers that the s. 80.4(1) rule, which does not impute income to the employees given the low prescribed rate, trumps s. 6(1)(a), which otherwise would recognize a benefit based on the interest rate differential between employee and regular credit cards.

Scott Armstrong.  Summary of 6 September 2013 T.I. 2012-0463501E5 ("Reduced Interest Rate Credit Cards") under s. 6(1)(a).