It’s seems feasible to correctly estimate the water usage by doing an initial water meter reading and then cycling through zones and entering the change.
Keep everyone in the household from using water for an hour or so and then cycle each zone for 10 minutes with a pause to read the meter between zones or however long required to get an accurate reading.
Then, within the app, you could enter the initial and after meter reading after each zone runs for the specified period. All subsequent waterings the app would extrapolate a very good estimate for actual usage knowing the flow per time per zone.
I can see however that this may cut into sales of the flow meter being sold.
Thanks! Great product!!