Avis/Budget are pretty bad about this, quite honestly. I had a recent Avis rental where the agent said "I recommend such-and-such car," I said OK, looked at the estimate, saw I'd been upcharged, and refused it. Don't recall whether I ended up with a car in my class or not. And when I was returning at Avis at ORD (had to go inside to rent b/c it was the middle of the night), the Budget agents were pushing upgrades hardcore ("oh, there's 3 of you and you've reserved an intermediate, you'd be SO MUCH MORE COMFORTABLE in an Excursion," etc.).