I have my sincere doubts about the authenticity of pretty much all sim aircraft - and racing cars for that matter.
Realistic and authentic, to me, are relative terms where computer simulation is concerned.

However, I think a good estimation of the expected performance could be made. After all, as shown in the Farnborough video, virtual A400Ms were already being flown by the developer/manufacturers.
There's also this little phrase in the docs:
So you know from square one that you're not going to get the completely real deal.Some features may not be correctly rendered. Not all the represented systems are simulated. Wilco Fleet : A400M has been developed within the limits of confidentiality.