Yes, I posted in Arizona Turf Water Consumption and What Changed in Flex Scheduling, drawing similar comparisons. I’m not sure about the use of wind data on a PWS, though - I use an airport station.
Unfortunately I don’t think there is a perfectly standard method of calculating ET, so I figure YMMV. (There’s Penman-Monteith but apparently there are different ways to use it.) I’d like to hear from Rachio about the differences in methodology since I’m an engineering geek who likes numbers. 
But for now maybe we just use crop coefficient as a lever to compensate.