Perhaps, sometimes, the NCO or EM adding to the files entered the date of the telex or other report. Also many casuality reports cover a span of time, leaving open the possibility of mistakes in record keeping. I've always found a lot of differences between the dates recorded in Berlin and a "closer" recorded date in the field like an evaluation, a promotion recommendation, or as you mentioned, a KTB. In the case of field grade personnel the KTB sometimes elaborates as to time, location, etc. I'd consider that far more accurate than an entry made after the fact hundreds of miles away. The same is true for wound dates, assignments, etc. Often the handwriten biography of the individual lists his actual date, while records keppers recorded an "official" date that is often different. Likewise, the longer after a fact its details are recorded, the greater the variety of dates appear. About the only was to confirm is to find & research the predecessor and successor at a given posting. The lower the rank and assignment, the more difficult it becomes.