That was my point exactly: Rachio is not interested in supporting it's users. It would be incredibly simple for them to add the functionality but they refuse to. After all, computers are really good at math so why can't they add this simple function to their software? Why do they absolutely refuse to support anyone other than those with lawns (inch/hour is designed for sprinkler systems, not drip irrigation). The reason is that they are simply not interested.
I had a conversation with their rep and he reiterated to me that 1) they had no interest in supporting my request to add GpM or support drip systems and 2) that they had no interest in allowing user local control over their system.
With Rachio, if the net goes down, your hosed (if you pardon the pun). All commands are stored and issued from their systems, not locally. And there is nothing you can do about it.
My ultimate solution was to dump Rachio altogether. I ended up trying a very good competitor's controller (not going to give the name but it comes with 8, 12 and 16 zones, and has touch panel control as well as phone app and web control and stores everything locally so if you disconnect from the net it's still there. I liked it but then my brother showed me his system controlled by a Raspberry Pi which had a lot more features and allowed infinite zones and cost less than any of the other systems (admittedly I had to program it myself).
So now I am Rachio free and my yard is loving it and I have a lot fewer headaches and don't have to worry about Rachio watching everything I do and changing things without my knowledge or permission.