It sounds like you're talking about alcohol you've brought in within your duty free exception (or at least cases where they've waived the duty). I'm talking about the duty you pay on alcohol beyond your personal exemption limit.

I think what you pay is determined by your entry point. But for any province, you have to pay duty + GST (in some provinces also PST) + some kind of provincial "mark-up" determined by god knows what factors. I'm pretty sure the AGLC has its own liquor mark-up despite the privatized ('free market') liquor distribution in Alberta, though I don't know how it compares to those in Ontario or Quebec.

TBH I still don't really understand all the bizarre 19th-century laws governing the distribution of alcohol in Canada. I think it may still be technically illegal to transport alcohol between provinces, though obviously they have no way of enforcing that against individuals.