People often underestimate the gallons per minute for a nozzle or whole zone. Most residential spray zones in our area are at least 9-12 GPM, sometimes more. So, it doesn't seem unreasonable for yours to have ten, 9 GPM zones push 90 gallons of water in ten minutes. Unless you know your GPM per zone is a lot lower.
I think most of us who are tuned in to our water usage and controller scheduling become very aware of the amount of water being used to water plants. Those who set it and forget it, become aware of their usage when they get the water bill!
I would say Rachio users have become some of most savvy water users and smart controller users in the market.