There's something I'm understand about your calculator @ldslaron. What's the equation that you use for your PR ? The spreadsheet is locked and the equations aren't listed, so I'm not sure what you're assuming.
Are you using it with Flex Daily ? If so, how do you guarantee the runtime ? The method I used was to put in your root depth, available water, etc. Once all that is done, Flex calculates how many inches it will put down each cycle. I then use that inches-per-hour for my PR calculation.
PR (in/hr) = Total GPH per plant * Watering Depth (in) / Watering Value (gal)
In my example, Flex wants to put down 1.19 inches. So, if I have 1GPH per plant, and Flex says it needs to put down 1.19 inches, and I want to put down 1.5 gallons, my PR is
PR (in/hr) = 1 GPH * 1.19 in / 1.5 gal = 0.79 in/hr.
The runtime will be:
runtime (hr) = Watering Depth (in) / PR (in/hr)
runtime (hr) = 1.19 in / (0.79 in/hr) = 1.5 hr
The #gallons work out, since 1 GPH * 1.5 hr = 1.5 gallons, which is what my goal was to deliver.
With your calculator not using the Watering Depth number (or Inches of Water applied), how do you tie it into the Flex runtime ? For a 1 ft diameter shrub, Water-Use-It-Wisely recommends 1.5 gallons. Your calculator correctly pulls out the 1.5 gallon number, but your calculated PR=2.04 in/hr for this example. If I used that in my Flex schedule, my runtime would be
runtime (hr) = 1.19 in / (2.04 in/hr) = 0.58 hr
The #gallons put down would then be 1 GPH * 0.58hr = 0.58 gallons, which was not the recommended amount.
Maybe you're using a fixed schedule and setting your runtime manually instead of Flex where it does the calculation ?