It's just the world of officialdom conflicting with what was sometimes used on the ground. Many a confused book has mixed up Spitfire official designations with log book information as sometimes the aircraft modification arrived at the field before officialdom had caught up. I.e. the Spitfire LF.IX (Merlin 66) being listed as the IX-B in log books because they needed some way of designating the revised IX.
Bf109 may have been what was stamped at the factory but in the field equipment picks up all sorts of different names. Or two different levels of bureaucracy don't talk to each other
WWII is full of these weird little stories.