why do my BOMs populate differently between my assembly and my drawing

Below you will see exactly what is happening to me. My equation to populate the length of a bulk part (2.0) works fine in the part, and in the assembly. When I put this same equation into a drawing I get a completely different value (50.8) and I don't even know where it came from.

1) Why would this assembly and its drawing give me two different results?

2) If #1 can't be answered, Is there a way to find the origin of the computed value for a BOM cell so I can trace back to this odd number showing up?

SolidworksDrawings And Detailing