Another issue with this is that you need to account for the "K" factor. In flat plate layout, when you bend sheet metal, the bend allownce for the bend is not the distance of the outer surface, rather it is at some point between the inner and outer serface that is a function of material hardness and the method of fabrication. The inner portion of the material compresses, and the outer portion streatches. There is some point within the material that it neither streatches or compresses and the length of this arc is the bend allownace for that bend. The "K" factor is the percentage of thickness from the inside surface that has no streatching or compressing, the neutral radius of bend.
I don't have TC pro 16 with mechancical yet, so if it is already there, disregard.