battery firmware

We know that we have to update the battery firmware. We know that battery from Phantom 4 fits on Phantom 4 Pro. My question is: the battery firmware used on Phantom 4 is diferent from firmware used to update Phantom 4 Pro's battery? If so we have to have battery for each on of them separatly...

Exactly what are the differences, and why do they have to have different firmware? I would love to be able to exchange the batteries between my P4 and my P4P without having to update the firmware every time I fly. Does anyone else have this issue, and have you ever flown without updating the...