So if you are saying everything is fine with 1/4 the required input power, then of course you care little about the lost signal to noise, the increased distortion, etc. along with less the stellar output. Best try it all over again with a full signal and see what happens. Hopefully you do not apply this principle to everything else in your life.
By full signal, you mean you're aksing him to not have a crossover and let his atmos speakers deal with the bass?
Why would he do that? It makes far more sense to crossover the atmos channels at a pretty high frequency.
I think if most people do REW sweeps and pack dual subs calibrated, they'll be surprised how high their crossover should be. the higher the crossover, less demands on the speaker = less need for power.