Jack:
FWIW: the OEI H-V I can look at says (in the little box above the diagram)
Model: MV-22B
Date: December 2002
Databasis: Estimated
Configuration: FE = 33.0 Sq Feet
Engine: (2) AE1107C
Fuel: JP-5/JP-8
The Dual Engine Failure chart is based on a 2009 "Piloted Simulation."
I don't remember if that means two test pilots putting the engines in idle, and seeing how soon they got the airspeed/glide/auto performance they desired, of if they were doing it in a simulator. I think it means a couple of pilots were out there checking it out. (If I'm wrong, please advise).
The Single Engine Flight envelope charts I have leafed through are based on work done in 2009. Most of the single engine data, and "Bingo" profile charts, have a label of "Estimated." I suspect that they are well suited to use in the field. The Bingo profiles in the aircraft I flew typically worked out Very Well when put to use, in terms of fuel on board, what you thought you'd burn, and what you actually burned.
I concur with the reluctance by anyone to post NATOPS charts on the internet. I will NOT post what I have found. Call it an old habit if you like, but it doesn't feel right.