You could expect to get more here in a private sale if you could show something along those lines. But when trading in to a dealer during buying a new car, in my experience it's never mattered if I've shown a complete maintenance history or no history at all. Most dealerships (around here at least) use wholesalers for all but the most desirable trade-in's, and all the wholesalers seem to care about is market factors related to the make/model/general appearance.