They might be other "resellers" like yourself who wont pay end user prices,
The appraisals are a rough guide and by no means what you should sell for.
I've had names appraised for $xxxx and i just let it drop the other day.
If it is other domainers offering $x for a name you think is worth $xx they will expect you to counter offer and then meet in the middle.(sometimes) but dont get greedy.
as they need to sell for what you think they are worth to an end user.