The whole appraisal system is filled with too many variables and based on a lot of guessing. Sedo has a wealth of information available based on what end-users have paid for domains. You could probably do a better job doing your own appraisal with a little research of previous sales at SEDO/Afternic/GreatDomains, to see what names that might be similiar to yours have sold for.
Purchasing an appraisal by a Rep has never worked well for me. You might as well just start with
www.leapfish.com and then adjust accordingly, if you're going to buy one from Sedo or other.