We have on eceiling fan and have been considering getting two more for other reasons, this may just push us over the edge.

Well, they've installed today 4 dampers - 2 x 6" and 2 x 8"
and so far at least, it seems to be doing the trick. Suddenly both floors feel almost identical. They did say they might from time to time need to be manually adjusted, but only on extremely cold or hot days. Temps around here don't normally hit extremes, so maybe this will prove true.

After all the great insight from this board, we did get them to put in writing it would (a)solve the problem (b)not require constant adjustment (c)not effect efficiency

I greatly appreciate the input offered here.

GO HVAC guys (and gals)!