Well, you did kinda hit the nail on the head, when you mentioned that you 'negotiated' the hitch setup work into the deal, and didn't pay extra for such. 'Tis very common with RV dealers - when they aren't making any $$ on hitchwork, and its just thrown in with the deal, they're not really motivated to take the time to do it right. They just want to get it done as quickly (read: cheaply) as possible. Frequently the result from that is just what happened to you - hitch setup not being done correctly.
I had very similar issue happen to me many years ago when we bought a TT and made the mistake of having dealer install a dual cam. They started on the install, got the holes drilled for the cams, then tried to hand me the bill (over 300 IIRC) for the work. Nevermind, we had agreed hitchwork was included in the deal. Long story short, they stopped the install and I completed it on their lot (without paying them for the little they had done).
They too, though, had put the cams on in the wrong place (about 2" too far forward IIRC), and I had to drill two more holes and move them. That TT always had two extra holes in the A frame as a result (actually 4, as not long after that I removed the dual cam and put on a Hensley hitch). Extra holes was never an issue, though, and I owned it for nearly 10 (great!) years before we traded up recently.
My vote is, as long as the cam is placed correctly front to back, doesnt need to come forward or backwards any, then just put a shim of some kind underneath the cam to fill in that gap. Extra holes in the A frame probably would not be a big deal, but I'm not sure I'd do that for just 1/8" gap underneath that could be filled with a shim. Thats up to you, though, if you think the cams being 1/8" lower than they should be might could cause clearance problems, then move them and don't worry about the extra holes. Just make sure you use some rustoleum paint around any holes left exposed, to prevent rusting. Thats what I did.
Whatever you do, I would NOT take it back to the dealer and try to get them to make it right. They already did one 'fractional posterior end' (half ***) job for you, I wouldn't trust them to work on it again, especially when once again, with no more $$ in it, they aren't really motivated to put much time into making it right.
Will
