No offense, but what good is it if you know it's wrong? There is an alternative, but it requires some work:

Users can rate their own springs. Google is chock full of how to articles on how to calculate wheel rate.

That's how I figured out the chart is no good. And how I figured out a certain set of springs I received were actually two different springs (they were both marked the same, and in the same factory sealed package). Upon further inspection, the wire sizes were substantially different.

I can't believe I'm the only one who got "lucky". I can believe I'm the only one who caught it because I was looking.