No, they are not one switch per battery. On my 2018 Spartan K3 chassis / MADP, the chassis fuse box is fed from the battery side of the 150A breakers. So the position of the breakers has no impact on feeding the chassis PDU.
On my coach, one breaker supplies power to the generator and I believe the other provides power to the HWH. There may be other items that are powered through these breakers.
2018 Newmar Mountain Aire 4531