Something else very handy for color matching are "color maps" which are typically available at any paint shop or body shop supplier. All paint manufacturers have them available, they can't be tough to locate. Here's one showing unrelated colors but maybe demonstrates how they can be helpful:
By laying one of these sheets over an existing color something very, very close to the original color can be determined and mixed for the desired end result.
Keep in mind the above photo is for demonstration only---the better color maps will have colors broken out in separate sections, variations showing different aspects of a color very completely. "Red" can go from a blood red color to almost pink and those would be adequately represented.
What's slick about that is the paint code accompanies any one color, the OEM use of such a color could be tracked with that code.
Anyway maybe more than most want to know about paint colors and how to choose them.