most shops, and most pros who do touch up all day long for dealers like to do it to freshly detailed vehicles. for obvious reasons, because 1) the paint is very clean so you get good adhesion and its also much easier to see what you are working with since the surface is clean and any marks that can be polished or removed will have already been done so 2) using a machine polisher, clay, or other deep cleaning/decontaminating products can and often do remove or at least damage the fresh touch up paint. we always do touch up very last.
