Fabrication 2019
I was looking into making a simple report to provide the weight of duct parts but noticed the result was different from what I had come up with by hand.

Basic example:
12x12 24Ga Galv duct (no connections for example's sake) in the generic Imperial database.
Fabrication says it would weight 4.7925lb per foot.

The math I did says it should be 4.624lb per foot.
While this is a minimal difference, when it comes to making a much larger duct, adding insulation, connections, and reinforcement; I feel this issue will compound and the weights could be off.

A second issue is that in our own database, the weight will populate in ft and inches; the same duct example above shows as 4 5/8" for weight? 

Is there somewhere I can see where the system is getting its math and adjust if needed? Thank you in advance.

Generic Imperial database

Our database