You are correct, however, if one of our data-miners could be so kind as to locate the post(s) from Vape360...? That would be sufficient as the most official answer to this query regarding the IQ feature.
More simply explained, the IQ stands for INPUT QUALITY...which takes into account not only the battery, but the channels of electricity throughout the device. This means battery end cap threads, battery extension ring threads (if using in 18490 or 18650 modes), the connection between the battery end cap and the spring, the connection between spring and battery, between battery and chip/board, the chip/board itself, and the chip/board to the center pin...
So, in fewer words, the IQ reads everything from the center pin down, that plays any part in output to the atomizer.
While it is true that a battery under load would read differently than a battery not under said load, I have forgotten if this makes a difference to our dear old friend Mr. IQ...
I know that on my trusty v2.5's, I get a more accurate battery check when my atomizers are not connected to the device...but as the P3 is the first of its kind, I have no idea what else may be affected with the atomizer connected vs. disconnected.
Also, I have recently "updated" my TapaTalk app, so I hereby apologize for any spelling, grammar, or syntax errors.
I bid you all a farewell, and goodnight.