Take in a print out of what Peaty posted. That is total BS and simply the result of them being careless if you ask me. They should apologize and admit that they screwed up, but I doubt they will.
Oh and by the way, my car did not take the full factory amount of oil to get to the correct level (I let it drain for a good 5-7mins also). I think I added around 4.5qts and it was perfect. I believe the documentation state 4.8 if I recall correctly. An inch over the top notch might only be an extra 1/3 of a qt or so.
If you aren't satisfied with the guy's answer, go to the service manager, then GM, then SOA.
Good luck man,