Here's an update on my experience: I reserved a compact at LAX for 7 days with the D005297 code at $200 (inc. all taxes), half the price of the corporate rate I could get. Avis gave me a small Hyundai SUV - which I think was an upgrade. I'm Avis Preferred, and they didn't ask for anything additional when I picked up the car.

The only issue I have now is I want to extend the rental for another two days, which will cost me $41 a day before tax, which I hate to pay since it's way more expensive on a daily basis than the 7 day rate I received!