Your last line provokes a question as to why, therefore, it is now seen by Bell as needful of being demonstrated by simulation only ( assuming simulation means a full flight simulator ) rather than a flare to a power recovery demonstration.
The 609 is now fully a Leonardo responsiblity for certification. Bell is only in a limited supporting role I believe.
Certification for safe autorotation landing allows for limited damage to the aircraft to occur. My guess is that Leonardo does not want to cause any damage to their expensive and limited flight assets.