Li-Po's don't really work that way so you can't always sense the voltage drop.

In my case there's only about a two volt difference between a fully charged pack and an empty one. It starts at 12.6 volts and ends at 9.8-10.3 volts.

Now I use the timer in my 7CHP instead of trying to hear, sense, or wait till the motor cuts out.

I do have one advantage in LV cut-off though. I'm using a programmable ESC set to soft-cut so it cuts power gradually letting the heli settle to the ground instead of the hard-cut which it sounds like the EZ comes with.