Interesting fact.
If the differences are down to harmonics at the pickup location, then the 60s spacing consistently give the same harmonic mix as the 70s spacing when played two frets
As there are consistent differences and these seem to be bigger than those observed as you move up and down the neck, this suggests the 'harmonics' explanation is not perfect.
My bad, I was using the spacings in the video as being from bridge to PUP. Actually, it's more like 0.83 for the E string and 0.8 for the G. So that would be just over 3 frets for the E and nearly 4 frets for the G.
A clear contrast to the much bigger difference between bridge and neck pickups, where the equivalent harmonic mix for the two poickups is more or less open string and 12th fret.