As I suspected. These seem to be the ones that were intended (start of the war, 2nd flottila):
Aug1000=BF13
Aug1001=BF11
Aug1002=BF14
Aug1003=BF15
Aug1004=BF12
the numbers 1000-1004 seem to be related with a indexing system in the file. It has no relavance to a year or date, other than the month shown.
Hmm, you could try to spend 24 hours in each of them and find out which one is the real one.