Clint
I think Denis is just as confused as everyone else.
If you look at his type summaries and what he says regarding No 2937 he only lists it with N81 but says it was in use all the way to 11 June 1917.
Getting better and better doesn't it?
Trying to be serious I would say that French aviation and their aircraft have so many huge gaps that we may never know for sure what is correct or not. An educated guess in the past gets overruled by new research and so on.
Denis (hats off to him any day), as an example, is doing a very good job, but just the shear size of it makes it almost impossible for him to change a former error at every point it may occur.
Cheers
Stig