The "CustomValue" is what Poser calls "deltaAddDelta". But that last version you posted is confused. Where did the dependence on xrot go?

I'll go back to the code you posted before and tell you how you can fix it, because that's closer to working.

Wherever you have this:

valueOpMinus<br></br>
Figure<br></br>
lThigh:1<br></br>
JCMlThbendFwd<br></br><br></br>

instead use this:

valueOpDeltaAdd<br></br>
Figure<br></br>
lThigh:1<br></br>
JCMlThbendFwd<br></br>
deltaAddDelta -1.33333<br></br>

That should do the trick.

-- I'm not mad at you, just Westphalian.