Hi: I can't help you with this particular piece, but I can tell you that the designer very seldom signed pieces of Scandinavian glass, particularly production pieces. The writing would be put on by someone assigned to that task. It might be the same person signing for quite a while, which leads to similarities, or someone else might take over, which leads to some differences. Occasionally you will get signatures that seem to deviate from the correct spelling somewhat, or when the tool has slipped a little when signing.
Very nice piece, btw.
Hope this helps.