I was wondering about that too.
My understanding is that AVR, Amp and subwoofer consumes energy in irregular manner. If u use more, it consumes more.

Meaning that if u play less boomy videos, subs being utilises less, it will consumes less. If you tune up the volume, subs and amps consumes more power to drive the speakers, hence it consumes more in the end.

Pls anyone can correct me if I am wrong. I am learning too.