I believe that to crow2k serve the fold tables that are required by the inventor for the development of the folded sheet models.
if well remember, depending on the material (for example there is difference between stainless steel and carbon steel), the thickness of the material, the radius of curvature and the angle of curvature (then the knife of the bending press used), varies the coefficient that says where the neutral axis of fold falls (the one on which the inventor calculates the development).
who has experience in this regard, I believe that these tables are kept tight. I at least never found anything about it (but I hope I'm sorry).
crudely, both for carbon steel and for stainless steel with thicknesses greater than 5 mm, for "street" folds I use the internal development with relative radius equal to zero, while for the magnets I make the development on the average axis. generally with these developments there is a few millimeters of error, but those who do the dieped (both internally to my company and externally) usually wrong much more in bending and therefore a greater precision of development is a little useless.