With Flex Daily, there are only 2 resultant numbers for each zone: The total water applied per week, and the maximum total water applied at one time.
Total per week is determined by the temperature/humidity/etc. (i.e. the weather, and it varies) and Crop Coefficient. Since we can’t control the weather, it’s best to control the Crop Coefficient.
The total water applied at one time is determined by the soil’s Available Water, the grass’s Root Depth, and the Allowable Depletion. Other factors don’t affect it.