Rick,
One issue that comes to mind is supporting boxes in t-bar ceilings. If memory serves me correctly, there was a drastic change between the ’96 and ’99 codes. The ’96 required rigid support of boxes and it could not be attached to the ceiling system. The ’99 allowed the use of ceiling wire support provided it was attached to the ceiling system. I don’t have these code books with me to check but that’s how I remember it. This would be a case of the later code making things more lenient and a possible problem with Jim M’s AHJ.
