Gee, I don't know. BUT, what I do know is that when Jim Winey decided to make Magnepan speakers 6' high, the listener was treated to a source that more closely mimicked the experience of being at a live concert. The "sound stage" of a concert is the hall you listen to it in. Most halls are designed to provide a quality listening experience that is as tall as the hall and as wide as the stage.
When you first hear Maggies that are set-up properly in a room that is decent, you then may understand the concept of reproducing the live experience. If you wish to call that "sound stage" or "image height" then feel free.
Another interesting fact is that, soon after others heard Maggies, THEY started making their products TALLER. Wonder what caused that, eh?
The experience of sitting in YOUR ROOM and listening to well-set-up Maggies driven by superb hardware is one that SHOULD remind you of the live concert experience. Call it whatever you wish; to me, that is part of the goal of all this.
Cheers!