It really depends on the paint and the method used to paint it ... I had a discussion a while back with a body shop manager from a Cadillac dealer and he swore that with the new system they used you could wax it the day it came out of their booth

... technology with the new water-based clearcoats is much different than the old enamels, laquers, and other single stage paints, so it would be a hard call to give an up to date assessment ... either way I'd go with the shop that painted it as they are the ones who would be giving the warranty