Thanks for the note. I don't think I follow what you were getting at. In my example, all I did it change the way the dimension is displayed from ANSI to Stacked Fraction. The units, fractional accuracy, etc were all left constant, but the reported size of the object changed from 3'4" to 3'5". To further confuse things, this changed only for the 3D object and not the simple line.
It seems to me that simply changing the way a dimension is displayed should not change the reported size of the object.
If I'm missing something please let me know.