The information on Potters site just relates to business strike coins which use a different system to apply the edge lettering. (Also the large and small font edge lettering appears to simply be new and worn edge dies.)
I am still at a loss on these proof edges. I still see no reason for the extremely rough surfaces, and I also still think it almost looks like the lettering has broken off the edge dies. (The notches where the edge dies come together is normal and should be there.)