Peter,
Sorry, I read your first posting, and seem to have missed the second one for some reason... 'trigger-happy' with the old mouse, I dare say!
You mentioned this...
"Additionally, as there was only one Staffel in the unit, there was no need for a fourth aircraft code letter."
... from one of your sources. I think, effectively, that was the point I too was trying to make. At least I was heading in the right direction...
.
Paul