My understanding is the same -- cubic feet drives your sub sizing, square feet tends to affect distance from the speakers which affects your main / center / surround sizing.

For full-range speakers, I guess both cubic feet (bass) and square feet / seating distance (everything) make a difference, which is how we keep ending up with M80s



M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8