Jaxa
I see where you are coming from.
Unfortunately I have lost my copy of the work I did regarding u-boat numbers, flotillas, etc. However, what I did was take the u-boat numbers of the boats assigned to the relevent flotilla and use those numbers to ascertain what type of boat they were.
The information was obtained from Uboatwar.net as Uboat.net does not list the vessels.
Hence the apparent discrepancy.
