Turning on “all zones” is simple, and you can increase/decrease intensity for all. I’d tried to select two zones at once, and set an intensity level applied to both, that didn’t work. Ultimately figured out that you CAN select individual zone, set intensity, move on to additional zone, set THAT intensity, then both can run in parallel. While not immediately obvious, it’s certainly powerful, so no complaints. Just a little user interface testing in future should make it perfect.