Yeah, unfortunately, sometimes you have to go back and have them redo things. Try to keep the whole thing amicable, you're more likely to get a good resolution if you and the shop don't end up hating each other.
Let them know that you consider yourself more particular than the average customer, but that you're NOT unreasonable.
Say "we" instead of "you"- approach them like you're on the same team, trying to get the same result (your car fixed right and you a happy customer and them a shop that's glad they did business with you). Don't be a pushover, but don't get all confrontational either. Treat it the way you'd treat a mistake on some paperwork, just something that needs to get straightened out. It's easy to get too emotional where cars are concerned.
"We seem to have a little problem that looks like either contamination under the clear or something else causing a rough texture. I don't know if it needs wetsanded or reshot, but I'd like you to take a look at it and see what we should do."
"Normal? Nah, I've seen plenty of repaints that were smooth as glass. You sure wouldn't expect me to accept this if it were on the middle of my hood. I understand that things don't always turn out perfectly, but I bet you can get it a lot better than this. What do you think we ought to try first?"
But be willing to accept that it might not turn out perfect. After multiple redos, I finally accepted that my S8 will never be perfect again (post deer-incident) and while it bugs me, life is too short to stress over it.