Some of the German states commonly did this with their postal stationery. Ffejy, you will notice on your scan the words 'einen halben' which is literally translated 'one and a half' - which is the denomination on your cut square. This would be for one and a half Schillings. I have scanned a postal stationery item from Hannover denominated one Groshen and it too is overprinted accordingly with the wording 'ein Groschen" for one Groschen. I also scanned a portion of the back of this stionery cover with the same inscriptions.
i think this was done so that there was no confusion of the value of the stationery printings at the time (?)
Hope this helps?
Chimo
Bujutsu


