Hi Chris
I see I crossed with HN39 in cyberspace, but still :-
Now, can you confirm that the chart is from a post-accident flight test? In which case, was it considered that the "deterrent buffet" experienced on the test flight was LESS severe than on AF447, or MORE severe?
I don't think you are going to do any better than section 1.16.4.2 of the final report. That says AI did special post-accident tests at as near as possible to the accident conditions and the test pilots established the AoA at which buffet reached deterrent levels.
If that chart is the result of those tests, as it presumably is, then it shows values appropriate to AF447, neither much more nor much less.