I agree. I've never been on a fireground and had someone yell, "We lost the house because you didn't divide by 12!" Fireground math is a very rough science. Every engine in our district has pre calculated charts for every cross lay and discharge so you aren't doing the math on scene. Additionally, once you deploy line you have a radio and can ask the engineer to increase or decrease pressure with no math required.

A much bigger issue is the lack of recruitment and volunteerism in the American fire service. People simultaneously don't want to increase property taxes to fund career departments and they also don't want to volunteer. Communities can't have it both ways. Lack of staffing is a far greater risk than whether I'm dividing by 10 or 12.