Whether you call it a markup or a dealer fee for handling the paperwork, it gets pretty salty at times. Still, a dealer can help a lot, especially in getting an idea of CLEO reaction.
Some CLEOs think they are guaranteeing angelic behavior on the part of the applicant forever; they are merely stating that there is no local law which would be broken by approval.
Actually, this covers BATF's fanny, in case they don't know about some local law that passed last week. If something does go haywire, they don't want to read that "BATF approved the sale in spite of the new Dogpatch Village law..."