Nice set of measurements !

The diffuse field looks about 'right' to me.
The OW does not seem to jive with what I am hearing, in this case.
It suggests a bass-less (steep drop off below 100Hz) headphone with piercing (+10dB) treble.
To me they sound very mildly U shaped and only lack some sub-bass (and upper treble) extension.
Can you post your sonic impressions as well (how they sound too you ?).
CS is all about linking measurements with what we hear, not just plots.