This was just a small sample really, and not meant to be proof of anything, at best I was hoping it wouldn't disprove the theory.
It would be nice to do a more exhaustive test, but I don't have that sort of spare time or resources. It might inspire someone else to give it a go and see if they get different results hopefully.
I thought it was interesting that die 34 seemed to be more consistent at the muzzle, but had quite a spread downrange. So I don't think you can say with any certainty that if it's good at the muzzle it'll be good downrange and vice versa. It seems likely, but a more reliable test would be to just ignore the muzzle and only chrono downrange.
I think chrono'ing at the muzzle will give you a good indication of whether your gun is delivering a consistent blast of air, but chrono'ing down range will tell you whether the combination of gun/barrel/pellet is consistent (and likely to give a good group)