Ok - More research.

Even more bizarre.

I just created a large scene.

Set the grid in the modeling room to 1ft and draw every 1.

Create a box thats 1x1x1 grid space (whcih should give me a 1x1x1 ft box) and it shows the box as 1,200ft x 1,200ft in the modeling room...but that is not what I have the grid size set to.
Exit the modeling room and its shown as 1,200 x 1,200 x 1,200 feet in the assembly room as well.

Maybe I'll just stick to using Small Scene settings since that seems to be the only one that works or I can wrap my head around.