The older distortion plots showed substantial distortion in the bass but the numbers were for 500 or 1kHz or so. There was no correlation and the weighting in the final 'rating' also was a bit off because of this.
It's just the way that Rtings rates... all measurable numbers they got out of the measuring devices (not from the individual In ear mics) and their weighting produces a number. That differs from Harman rating as well as the subjective rating from Oratory
For this reason rating headphones is nonsensical. Sure you get a ranking in all cases. You can put them in a list and publish it as evidence but in reality it isn't. In fact the rating from
@crinacle makes far more sense to me than the Harman rating and mostly would agree with that list (the ones I know)