There is a difference in this between Poser6 and Poser7 in this. I remember when I made my beachchair I wanted to make it foldable, but valueOpDeltaAdd didnt work and I had to use the new valueOpKey but that doesn't work in Poser6.
There is a workaround for this: change the versionnumber in the cr2 file from 7 to 6 and use valueOpDeltaAdd so it will work in both versions.
The advantage of using valueOpKey is that you have more control, at least that's what the manual says, haven't tried it yet

my €0.02

Bopper.

-How can you improve things when you don't make mistakes?