If Zack < CCSeph < FFSeph, and Zack is easily in the Ma3/4 area, then Cloud will be hypersonic.I disagree with Zack being mach 3/4, he has the reaction time to avoid bullets, sure, but meh. That doesn't translate directly to Cloud being hypersonic via powerscaling though.
Sephiroth toys with Cloud, this is a plot point. Never goes all out on the kid.