Interesting data and awesome work! Thanks!
So frame rate is 3.3 but this is already past useful because the servo can't update that fast.
Min latency is 2.2ms with average being 5.3ms.

We still have no idea what the M12/M12-S specs are with you test. We also have no idea if Sanwa's stated values are for minimum or average latency. Do we even know if their specs were tested at the component or the servo level?
It would be neat to see the following two things:
1) specs for M12S with your tests
2) spec of 4pX with a 614 Fasst Rx ( I assume it automatically links on C2 mode)