I can't put words in Lee's mouth but I think what he's saying is the stroke is exactly what you and all the other certified instructors are saying but in the finish/follow through, after the ball is gone, the elbow drops. The follow through is simply longer than if we don't allow the elbow to drop. In this kind of action the wrist plays less or maybe no role in the stroke. I'ts more of an arm stroke. The cue does the work. Even though the ball is gone, "the motion" is what counts. If "the motion" doesn't matter, then "follow through" would not be a critical part of a stroke, afterall the ball has already left. We all agree that follow through is critical. Now it's simply an argument of degree.
The problem I see in this, is coaching an elbow drop before a sound/classical stroke is established. Again not to put words in his mouth but I think that's why he calls it an Advanced Technique. I developed an elbow drop because it seemed to give me more feel and control of the Cue Ball. That's my game, 3C. I'm not saying I'm right, just what I do and why.
Now that I've been reading on elbow drop I've started looking at top players and see that the very best Snooker players do in fact drop. Is this a fault, a fad, or the new way? It looks like all the top players drop, not just one or two. Take a look. Also look at early videos of Allison Fisher vs Current vids. You will see a difference. Is that a fault she picked up and needs to get rid of or did one of her coaches teach it? I don't know.
I don't claim to have the answers or to be an expert. I'm just a bum swinging a cue. But I'm a curious bum wanting to learn as much as I can.
Ok I left myself wide open. Give it to me if I need it.