If its flaked like that in such a short time, whats the rest of the truck going to be like when you start using it, a stone chip could end up being more than just a stone chip when out on the hwy. i hope the rest of the body has been prepped properly or you are going to have lots of paint flaking off when start driving it.
I am not a painter, just a floor sander polisher, but i do know that if i don't sand my floors down between coats,so as to give them a key to stick to, they will start to delaminats or peel in a very short time. I would be asking your painter to take a trip to your house, so he can see first hand what his handy work looks like. I am sure when he sees it for himself he won't say that its a common problem.
barnsey