I'm having a little trouble distinguishing this from a regular sankyo.
Maybe it's just the people who I've trained with.
Most people just put the arm in the inverted position and twist while applying upward pressure. This usually results in localized pain in the wrist and forearm. But, this does nothing to control Uke's entire body. It's just painful. If someone is resistant to pain, it wont work.
Taking control of the bones, themselves, in the forearm and shoulder...as well as controlling Uke's center is different. And this way of doing this is much different from the Sankyo I've experienced.