the chemotype doesnt tell you exactly how much of each kavalactone present in a given root, it only tells you ratios. Lets say you had a strain that has a chemotype with kavain as the number one kavalactone. It might have 38% kavain out of the total KL content. the other kavalactones might be less than 20% each. Then take another strain that also has kavain as the number one kavalactone, and the exact same chemotype lineup. That strain might be more balanced evenly, or more "full spectrum" and end up having only 25% kavain, but around 20% of several other kavalactones. The first strain you tried has 13% more kavain than the second one, despite the fact that they are identical in the order of kavalactone content. the second one probably has a bit more DHK or Yangonin etc than the first, since it is more evenly distributed.
All that said, I feel chemotype is very helpful in determining your preferences, especially if you can see a breakdown of the percentages like you can on Truekava.com. Me, I like anything that has a close KL content to Moi. I like a healthy amount of kavain and sometimes a decent amount of yangonin. That's the extent of my understanding of what works for me.