But it's not real and doesn't make sense. O-scopes measure what's actually happening. The energy is being dissipated, not doubled.
I appreciate you trying to find the gap, but that's not it.
I was trying to make it simpler by using the volume example. But failed.
There is no increase in air pressure or volume. Period. The system works by taking sound energy out of the air by oscillating the speaker in the ear cup exactly opposite to the sound waves. To get more pressure you would need to pump more air into the cups. So you would have to have a fan or something in the headset. And the air would leak out the cups. And any change would be minuscule compare to the pressure changes associated with altitude, or someone blowing your ear. And, and, and. It's just a total non-starter.