@LVhome. Taking advantage of added Flex 'flexibility' requires digging into all of the settings, or a good deal of them anyway. You need to take the time to read through some of the Rachio articles, etc.. If you don't have the time or inclination then stick with As Needed and you're still much better off than with a 'dumb' controller.
You could always do what I did and start with As Needed as your "live" irrigation solution, then play with Flex on the side as your schedule allows. Just disable As Needed schedules when you're playing with Flex schedules, instead of deleting them.