Sorry, I should have been more clear.

I can take 3 bags with QF to LAX. On the AS flight, each bag is paid for, so I will only be taking 1 or two for the whole journey.
If there's a chance that the Qantas Checkin person would check my bags all the way to YVR (against their stated policy), I could avoid having to re-check with AS and pay the fees. If there's a chance of this, I might just take 3 bags and try my luck. If the chance is slim-to-none, I'll just take 1 or 2 at the most.
I know the fees are not that significant ($20/bag with AS, up to 3 bags), but it all adds up, hey? =)