On fitzmall.com, the posted no-haggle prices for 2013 Avalon V6's, at the Gaithersburg store, are $1300-1500 off MSRP, while Avalon Hybrids are $500 off. It's been this way for a couple of weeks, I think. When I first started looking, in January, the Hybrids were posted at MSRP (above MSRP including Fitzgerald's loaner car and service voucher package), and weren't moving at all. They dropped the prices drastically, brought them up a bit, and seem to have settled at $500 off for now. I think this gives a window into the demand for these cars, versus the low inventory, in this specific area.
It's harder to tell what's going on at a dealership that doesn't post prices. sesame seed, I'll throw out the idea that your car sat on the lot for a while because they held out for too much money, more than the car is worth in the current market. You walked in at the time when they were willing to bend.