Can't Make a New/2nd Flex Daily Schedule

I know I can’t run two Flex Daily schedules on the same zone(s). And I already have one. But I would think that if I go in and Disable my existing Flex Daily, and confirm it’s the case because my zones aren’t getting any water, that I could go in and create a New/2nd Flex Daily schedule. But I can’t. When I try, it won’t show any of the zones that my other schedule uses as being available. Why? They aren’t currently being scheduled.

Right now I’m doing this for illustration and testing purposes, seeing what affect changing days and such has on the schedules ability to cope. I could also see doing it being unhappy with the current Flex Daily schedule, but wanting to keep it as a backup when creating a new one, in case the new one isn’t as good. Or you forgot the settings.

So, I don’t understand why I wouldn’t be able to create 2, as long as only 1 is enabled. Is that the case, or am I missing something?