While focusing on shaving down numbers, don't forget the old ~1ms/foot (at all sample rates
) for sound.
I suspect like Propower I do get concerned about systems with higher overall latency caused by all the things mentioned, and folks picking up on some tecnical single figure of merit that is only part of that and over worrying about beating that number down.
It can be interesting to pull out a microphone and another DAW (or even the one you are using) and measure actual total clap/click latency round trip times.