Explaining stuff was never my strongest point <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />
But I guess you are right, maybe its just a different way of looking at things?
Maybe a better explanation would be that when going upwind one tack gives better VMG, and downwind the opposite tack.
So if upwind starboard is better then downwind port is better.

Is this any clearer?