Paint question...matching metallic

[PolishPstroker]

I had my front bumper and grill shell resprayed because of some chipping and scratches and the paint is off enough from the rest of the truck that it bothers me. It is CX code charcoal grey metallic and was mixed at a local autoparts store to the Ford CX code. Question is how I can get it to match perfect? Would buying a quart directly from Ford solve my problem or could it be that metallic is just very hard to match because of the way the metal particles lie from how it's sprayed, or air pressure, or static electricity? Any input would be helpful, thanks.