hok fading is a bad rap it got decades ago and its not really true...sort of. hok has been known for many years for their dye candies. these do fade easier than pigment colors but to group hok as a whole as a product that fades is just not accurate. only the candy dyes fade. the rest of all their products are no different than any other paint mfg. most of that major paint mfg have candy dyes in some type of custom line and all those fade just the same. there is nothing special about hok though either. i can take almost any color they have and go to my wanda rack and mix it. all their metallic and pearl colors are just formulations like anything else. other than the special effect stuff, hok doesnt have any special pigments that none of the other majors have.
mixing your own color is not an issue but like crash said, you need to make an accurate weighed formula that you can repeat. almost every color i have sprayed over the years, i have formulated myself. rarely do i use a color code from a car. also a little note on hok, if you like a color of theirs or want to mix a couple of their colors together to make or tweak the color to your liking, dont expect in 5-10 years that those colors will be available to mix again. hok discontinues colors colors and paints all the time.