A Zombie skin color scale idea

Have you ever note that in every zombie movie the dark skinned zombies, like the black guys doesn't change the skin color?
Doesnt matter if the zombie skin becomes green or grey, the dark skinned guys doent turn green or grey
Maybe because will look weird, more like Gamora from Guardians of the Galaxy than a zombie or whatever
And that why I made this proposal of zombie skin colors for the darker tones of the pitzpatrik scale.