Quote:
The lower three values were printed with 4 sheetlets of 25 (5x5) in a plate. The letter/number at bottom center (ex. I/4) is a sector number that denotes the plate (ex. I) and position (ex. 4).
Thank you PostmasterGS for explaining how these panes where laid
out on the sheets.
One question. What does the
S stand for ?

PostmasterGS, your knowledge and the wealth of material you
have from this era of German philately is outstanding and
probably unique.
Also your constant efforts in helping all forum members
in any questions we have is really appreciated.
We are lucky that you are here on this forum.