The discoveries continue,
Well somewhere along the way since the 2010 design upgrade they also change the yoke.
See this pic of the 1st vintage from my 2003 HP DC. You where able to spin the nut when adjusting the DC very easy. There was room to do this.

Now look at the 2010 yoke with the molded in steel black bar above the nut. Now in 2013 that molded in steel black bar is gone. Spinning the nut "must" still be possible however it may not be as easy as the 2001 HP DC vintage. On the 2010 vintage you could not slide the cam arm back and forth on the yoke without spinning the nut as it was locked by the molded in steel bar.

The 2003 vintage adjusted very good/easy, just the heavy thick yoke could hit the WD bar if the installer did not setup the chain links under load correctly. The 2010 vintage I'm sure was a hand full, the 2013 vintage does appear to be better than the 2010. Never saw that before until mrekim posted. This is not part of any of the failures seen in this post, just a side line learning.
(Edited 11-28-13 to correct that the upper adjusting nut can spin in the yoke)