In my experience, you might be interested in two variables:
Root Depth - This, combined with AWC, determines how much water Rachio thinks your soil can store. I find a deeper root setting leads to much longer runtimes, presumably to get water percolating all the way down. Deep roots are a good thing, but this effort & water is wasted if your roots are only 3". I found getting AWC & root depth right got me to roughly expected watering durations.
Crop Coefficient - Rachio seems to use different math than my local weather station. At Et0 (crop coefficient) of 0.80, Rachio comes up with much higher daily water usage estimates for my lawn than the weather station. I dialed mine down from 0.80 to 0.60, and water usage estimates (in inches) came more in line with local estimates, and the lawn was healthy. It’s not clear why this is happening. Anyway, this reduced frequency of watering to where I expected. If you can get a local watering guide on daily grass Et, you can fiddle with Crop Coefficient until your daily evapotrans in Moisture Levels roughly lines up.
I do hope the Et0 thing is eventually resolved, I was initially rather excited as my local weather station even provides a ramp of Et0 through the months, and a range for different qualities of turf, so I was going to really maximize my benefit by following them precisely! I suppose I could interpolate their numbers…