Eric, good news is that I edited the post per your suggestions (including attaching the plan itself). Bad news is that I tried the fix which I THINK you recommended on the Roof dialog of the Wall Specs for the wall separating the main, upper and lower levels - i.e., I checked Lower Wall Type if Split by Butting Roof option and for the drop-down below that I selected Interior 6. Seems to have made no change at all to the results. Any other suggestions? Thx.