Well, weshould not underestimate the effects of even order distortion and frequency curve deviations. We will need empirical data to verify whether it is indded an order of magnitude less.
All I can say is that if the distortion is sufficiently high, it will have a significant effect, as will frequency curve aberration (even more so).

But of course, I agree with Wayne's post & yours, in general.
-akhilesh