Yes, I agree that you can add a flex schedule to a zone that is watering on fixed, but I would be worried about it running and overwatering until I got the zone setup dialled in. Another option could be a 'simulate' mode for flex that tells you when the next watering would be scheduled, and how long it would run, without actually running. Simpler just to provide the moisture level graph for all zones.
Maybe this should be a separate request, but I never know when Rachio is recalculating the moisture levels and predicting the next watering. It would be nice if either the system recalculated the moisture level whenever zone data is saved, or have a refresh button so I can see the effect of updating zone information.
Thanks for listening!