Maybe the bar stock was made in Essen or it was a holdover for a place of origin? My wild, rampant speculation would be that if Essen is present that the bar stock was made in Essen and then the bar stock was shipped to wherever. If Essen is absent, then the bar stock is of the same recipe but licensed to another facility outside of Essen. I'll dig a bit and is there a time frame when "Essen" was present & when it was not? Or is it just sporadic?
Jn. Henry Andrews Toledo Steel Works Sheffield advertise on tubes as Sheffield but I'm hard pressed to believe the bar stock came to Liege from Sheffield? But it is possible of course.
Cheers,
Raimey
rse