For transparency's sake let me say first that I may be biased in favor of Dirac Research.
Another measurement system would closer replicate the Dirac's graph that is representative of the average of the nine measurements, Dirac graphs are accurate... b.t.w. they have been validated by indipendent third parties but I cannot post the link because I don't have enough posts.
REW is accurate also... but I have serious doubts about that REW graph if it is a full bandwith one (that's the reason I conjectured that the correction had been limited to the low frequencies)
First I doubt that Rich would be satisfied with the garbled response above 400 Hz of that REW graph before the Dirac correction.
Second I doubt that the after correction graph is representative of a proper Dirac correction.
In a few words no creative tech guys moved from Germany to Sweden
may be something went astray in that REW measurement.
Flavio