Your thought is the same as mine, Galle. Most of what I know of Loetz is the glass made before the states merged to form Czechoslovakia. I need to locate a good book that has their last 20-30 years of production. I've looked, but it seems that most authors lost interest in Loetz about 1920. Another mark that is on the bottom of these types of vases is attached from a similar vase I recently bought. It is similar to the one on Antique Helper, but still different.
Anita