I have latest version of Rachio app installed on my iPhone 5s. When I was in the advanced tab of a zone, I clicked "Use Defaults". I saw the default values fill up the screen. I pressed back button. I DIDN'T press save button. I went back to main screen and again came back to same zone properties page. When I went inside the Advanced properties page, I see all the default values even though I didn't save them.
I had to go back to excel sheet where I noted area for each zone. I set the area correctly and saved it.
This is not a biggy. Thought you might want to know and fix it in next version.