IIRC USACi is a chart where both power and cone area is taken into account. Cone area doesn't usually win in and of itself because you still have limits on height of box and it must stay in the cargo area. Also crowding a box into the cargo area often robs you of the ability to move it around to find some more tenths. It comes to a point where the cars that get loud easily have the big edge, cone area notwithstanding.
I continually ask people why they always insist on whale-song tuning these days, especially if they plan to play actual music played on instruments.