In fact it only works if there's latency and said latency is in the same range as the time needed to finish punching.
That's pure bullshit though, as Accel can reflect bullets that are several orders of magnitude faster than a punch, meaning the latency in the system is extremely short.
One could argue that the sister network might have added some latency, but it has not been made clear what are the disadvantages of said network. More importantly, the guy speaks of Accel's power HE developped, meaning his counters are based on Accel's powers prior to his gun lobectomy.