How does the edge of the 09 Twin compare to the edges of the other boards? It may be that the 09 edges better than the other two. Whether it's compensating for a problem with your riding or whether you've gotten used to riding more aggressively because of it, dunno.
Couple of years back, I had two boards and my heel turns would wash out more with one board than the other -- the board would 'skip' a few times then I'd be on my butt. As SW mentioned, there was a problem with my turns. For whatever reason, one board would handle my turns better than the other -- and it was the cheaper one! Eventually I figured out what I was doing wrong and corrected it.