Well, he’s using a 5128, which is a different standard. I don’t think he measured this on a GRAS. So… those are not cross comparable either.
Here’s the GRAS measurement:
Again, bass difference shown here is likely more to do with the reference Clear than any actual difference. Unit variation is a thing…
But, the 711 couplers are rated for accuracy up to 10khz, and this is why showing it with in-ear mics is more readable and accurate for showing treble differences.