Codes are good for a historical reference, but useless for obtaining the color you have in your mind’s eye. The only way to get what you want is to start with a sample you like, get a color-camera scan, mix a small sample, and get a true paint matching wizard to start diddling until you get the color you like.
Metallics are even worse.
Im currently repainting my old beater 85 Ford F-150. It was originally done in a mid-range metallic blue. If there was any color in the world that should be sitting on the shelf, ready to use, it would be the standard blue used on one of the world’s most-produced vehicles.
Nope.
Worse, my friend and paint magician Kelly (look at pictures of the 2019 Concorso Italiano “Best of Marque” Alfa to see his work) has advised me that we must apply the color to the entire truck all at once, instead of cab one day and bed on another, as the metal flake paint WILL come out differently on the two days due to temp, humidity, astrology, or whatever.
Paint codes are interesting history, but not a precision tool.