Yes I agree, however, I suspect that the veritable 'night & day' difference I heard when Glenn made the change I mentioned in my system, was primarily due to him exploiting the sonic benefits of the amp's phase-inverting circuit (minimising active stages used), than anything relating to what you've described.
That is why I can clearly hear significant sonic benefits with
ALL the recordings I own, not just those that are "polarity coherent".
Like I said too, you now have an answer for why Glenn designed his amps to phase-invert the signal. Knowing him well, and the design goals he values, it’ll have been all about minimising the amount of active stages needed, and hence simplifying the signal path, in order to maximise sonic performance
Marco.