My experience in a word: Zero! That'll probably explain a lot.
I got this thing from a friend with the vague explanation: doesn't seem to work. I put the connector in an outlet and it worked. So me: great, it works after all. Didn't know about the plunging part. Now I do.
I believe, as you suggested, that the columns are frozen inside the body.
But why would that cause the adjustment rod to freeze also? I don't understand the connection. Even if the base is stuck, the adjustment rod should come out on top, or?
Sorry for being dense.