I just purchased a new vehicle and they check the auctions to see what similar vehicles sold for recently. At least around here they do. Most dealers will give you the same price for your trade. Mine was only a $22,000 vehicle, but dealers were within 500 dollars on the trade no matter what I buy as long as you make sure the trade is separate from the new vehicle otherwise you really don't know what they are giving it to you for. The trade price was the same for a Honda dealer, GM Dealer, Ford Dealers since most of them just wholesale the vehicle and seldom keep them on their lots like in the old days unless it's something they really need. Used Trucks are a dime a dozen right now.
I'm sure the dealer is having trouble finding your vehicle value from the wholesalers since it's so new.