Hey Andy B.,
If you want to do that it would be OK. I've found the same problems. As I see it, much of the problems lie with the paint manufacturers, and the EPA. A good example is Cletrac Orange, Martin Senour mixes the code for this color, it is an identical match for Prarie Gold, the formula even matches, and that is pretty much the story on this shade, with the exception of PPG Ditzler, they use the correct formula. It is not in the codes, these are correct in most cases, it is in the formulas. What I have been doing that seems to work well is, find an accurate sample of the color you want to use, about 2&quot;x2&quot; or so. Many paint suppliers can do a computer scan of this sample, the program will then generate an accurate formula to reproduce that color. The reason explained to me for the wrong formulas is there are so many shades that have been created over the years that the paint manufacturers go thru and substitute formulas that are 'close', for the codes that don't sell. Since we are in a very small niche in the market, we get the brunt of this. We simply don't buy enough paint to make it worth their while to keep the old formulas. So, I suppose we will end up needing to rely more on scanning for custom mixes. It was good to hear from you, I hope this answers your question.
Take care!!!
Andy