This in incorrect.
There is no such thing as "being incorrect" when one
doesn't post a fact, Using phrases like "there is a possibility..." and "it could be..." it automatically means that one posts a ...
possibility. So, please be careful on how you refer to people...

EDIT: Hence, I have to repeat the
question (on which the possibility refers in the same statement - because you cropped it off):
"Please do! (reproduce the findings) as it is opposite to manufacturer's claiming... It is (obviously) important for customers to know what is compatible and what is not when they are asked to invest a fortune on equipment... By the WAY... It would also be important for one to check if the cross-exchange complicity of H3/H3II & H4 backs, applies for different sizes of backs (which I doubt) rather than just checking if an H3D31 also works on an H4-40 body (which I suspect it should). You see... there is a strong possibility that the body can recognise a same image area size back (and thus correct for it for lens issues) but it could be that it doesn't recognise a different image area size back because it is "tuned" to only recognise (and apply corrections for) a specific image area size...