I think a more accurate way to figure out pricing is to do an internet search for a similar model. They may not be in your area but you can at least get a good idea of what they're going for.
As a side note, NADA had our old trailer with a value of something like $28,000. The ones I found online were running anywhere from 20-25k. Dealer gave us 20.
Keep in mind too, especially with newer trailers, a lot of people price them based on what they owe on them, not what they're actually worth. So that could explain some of the higher prices you see.