Wave loading never made good sense to me. I know some argue that it helps take advantage of some post activation potentiation mechanisms,...
Dropping down and working back up has always allowed me to hit my prior heaviest single for a double and with better speed and form than the first time around. That coach's argument may sound great in his own head, but the body works the way it does. The classic lifts are about power and precision and those are served by ramping up and then dropping back down and ramping back up. This doesn't work as well on simpler strength lifts like squats where speed and technique take a distant back seat to pure strength and being fresh.