Does anyone have a good sense of how to treat step down ceiling heights in calculating the interior distance qualifying for quality views? The ceiling is 10' at the windows, stepping down to 9' and then once again to 8' furthest in the large open space. Originally, we thought the ceiling height would be 10' all the way across the space and calculated our area for qualifying view to be 30' from the windows (3 x's the head height). But with the step downs, do we use the lowest point 8' for the entire space or a weighted combination? Thanks.