I have a minor issue on a new project. I have piped all of the lateral lines and mainline, and sized all the lateral pipe. When i try to size the mainline, it gives me an error message with the critical zone, that i have exceeded 5fps and then 3fps. So when i look at this valve and highlight it, it shows somewhere between 10-11 gpm, when i size it, it reads 15.8 gpm. Any ideas what might be causing this?