Any jobber can mix your paint. They want the paint manufacturer paint code, not the one on the trim tag. All manufacturer's colors will not be dead on to the original lacquer. The tints, especially the metallics, are not the same as they were on a lacquer system. If you are shooting Sikkens or another just call the tech line and ask for a lab match. It's done all the time. Having a sample is even better. If you are not happy with the match you will have to tweak it.