ITS the one problem with powder coating wheels, get a stone chip or curb wheels, you have to powder coat wheel again, it's not like car paint, you cant even feather it back, to just respray the mark, you need to strip the wheel completely back to bare metal and start over again, worst is when you get a chip with a powder-coated part, dampness gets in and eventually rust the complete surface it's on.
As a professional car painter, I don't understand why it's considered a great idea to Powdercoat car parts, of a car that will be used on the road, but just my opinion
Robert.