Latency and clicking issues

I have a MR816x plugged to a PC. I’ve set the latency to 64 samples = 7ms roundtrip. Is that about accurate or am I losing time somewhere in the chain?

Also, is it common to have some clicks/pops after playing 20 tracks on it at 64samples? I need low latency as I’m recording audio from a bunch of different gear simultaneously.

Thanks.