[RolandF]

It is not because of caligraphy. Those guys had been trained in Sütterlin script in their early scooldays and had been re-trained to use Normalschrift from 1941 onwards. The result are those hybrid scripts we find so often used by young pilots in their Flugbücher and other hand-written documents. Some scripts contain more Sütterlin features, others are closer to Normalschrift. After 1941 every years makes the difference in using Sütterlin for one year less.
My father born in '27 writes that way - a Normalschrift with certain Sütterlin features. I still learned Sütterlin ("Altdeutsche Schrift") at school additionally to the standard writing.
This makes it so difficult to read handwritings from that time and you have to know both scripts and its differences to gain a correct result.

Regards

RolandF