In this case I would not mess with the depletion — rarely should one need to adjust it from the 50% default. Something else is amiss. More than likely the precipitation rate (Nozzle Inches Per Hour) is too high and so the controller, based on that setting, thinks that plants are getting plenty. The next setting to look at is the Available Water Content of your soil. If all your trees and lawn are on the same zone, you’ll never get good results. Trees need deep watering (usually drip; don’t rely on the default emitter/drip setting in Advanced Zone settings! See the first link below to learn how to calculate a nozzle rate closer to what your trees need).
Some resources to learn from and apply to your situation:
https://support.rachio.com/hc/en-us/articles/115010542148-What-are-Advanced-Zone-Settings-
https://support.rachio.com/hc/en-us/articles/115010541708-Flex-Daily-Schedules-FAQ