We have both sets like you have and the one of the left scares me so I don't use it. We have a pair of them and I swear that any movement on the thing causes the jack to lower itself.
I prefer the jack on the right that uses a proper pin. We have several different kinds and they never budge.
Glad to hear that you finally got the sub-frame out! It's always satisfying to accomplish something...especially when it's been such a PITA
