Thanks for that - helpful. Seems like it's a gamble, which is a bit strange - you'd think there would be a clear difference between Premium and Luxury otherwise why would people pay the extra?

I'm fairly flexible on rental location too - how does Edmonton compare for this sort of car to Vancouver (Or Calgary)?

I really don't want to gamble with trying to get an upgrade - I want to book whichever class I need to book to ensure that I can reasonably expect to drive off with the best Sedan the location has in stock. To me this feels like I should be booking H, as I might get pushback from the location if I book G instead of H and then try and ask for a 528i or a CTS?

I usually rent with National where Premium puts you in an Impala and Luxury gets you something better but National do not seem to offer Luxury as a reservable class in Canada hence moving to Avis..

H/Luxury is coming back at 30% more expensive than G/Premium.