Best to check the WS website.
"Subject to the exclusions below, annual qualifying spend is one hundred per cent of the amount spent on eligible published base fares for WestJet-marketed flights you have flown within a qualifying year and, twenty per cent of the individual portion of the base price of eligible WestJet Vacations packages you have booked on or after August 20, 2018 and completed within a qualifying year."
https://www.westjet.com/en-ca/contac...estjet-rewards
So, AC uses Base Fare and YQ, WS uses Base Fare - I assume they don't tack on YQ. It should be the same.