I took a lot of boats in trade. The NADA was the basic guide that gave you a baseline price to work from. From there it was all about the condition of the boat/motor/accessories. If it was an exceptionally well taken care of boat, that was ready for the water, a well known brand (desirable) with a known good motor, then it would get extra value added.
Ripped seats, faded gelcoat, worn out carpet, and especially dings, cracks and scrapes would get the cost of repair deducted from the value.
I would NEVER take a trade on:
Anything that said "Travis Edition"
Suzuki two stroke motors.
There you go. Trade in basics.
Marble Falls/Seadrift TX