Just a theory, your tails are boot shaped "Swimbait style" tails, right? My theory goes along the lines of that you can have a lip or a swimbait tail. If you have both in the same proportions they will cancel each other out. Many of the older big wood baits had a small swimbait tail. The little tails did not take much action away from the plugs because the didn't create enough drag.
Tight lines,
Wade