I configured the Rachio as suggested above. Now the water usage seem more accurate. We made many modifications to Lawn after builder installed the sprinklers. Yesterday I tuned all the rotors to cover more of the zone they belong to. That should improve efficiency. The Rachio app came pretty handy to turn the sprinklers on or off from the lawn without having to run to Garage 
We had Flex schedule kick in today for the first time. Now I have better idea how it works. It is pretty smart. It didn’t water all the zones that were included in the schedule. It picked the ones whose moisture level is below a threshold and watered them.
I was little bit concerned at first with the estimate that the Flex schedule shown. Now I understand that it is the worst case estimate. Most of the times, the watering time might be lot less. Mine showed 330 minutes to cover 8 zones. But it ran only 130 minutes today to cover 4 zones I believe.
So far I like it.
Thanks for awesome product!