Yep, changed over in the 20s....
When the Industry directory for Solingen was printed in 1922 (have a few of them sold one to Ivan) they added a sticker label over the old (Pack Ohliger) company to the new Ernst Pack and Sohne.
This information is also in Anthony Carters book (German Knife and Sword Makers) Always for sale on e-bay and by me..
So a must have book guys...
Regards: James