@Jody Young I think we will have saved a decent amount of money not having to demo and poor a whole new foundation. We did have to add a couple large footings for new load bearing post locations, and also did a small addition on the back of the house. So there were some foundation costs, but for the most part we were able to use most of what was there.
Due to setbacks and the narrow lot, a new footprint wouldn't really have given us much more square footage without doing a very narrow/deep floor plan. Hence why we decided to go up with it.
@Aaron McGinnis AFTER ALL... It was a challenge to keep exterior walls and trying to use existing window locations. In the end, we re-framed several of the window and door openings. Next time on something like this, we will most likely take all the walls down, and probably completely demo the floor structure, as we had to replace numerous floor joists and level out the rest anyway.