I sell cars for a living. Let me explain a little more. When we get cars in on "trade" we will appaise them 3-5 back of wholesale book if its a luxury car.
Whenever i help a freind buy a luxury car used i always go off the wholesale book value as my target price as typically they dealers will still have some wiggle room in that price even after CPO and Recon fees. Auction prices are usually 3-4 back of wholesale book so if a dealer takes a car in on trade and cant sell it for the asking price they can still take it to the auction and break even or make 1,000 or so. Just a example