Of course, the type of manure, method of application, and timing of application all comes into play when looking at total nitrogen rates. It seems to me this nitrogen rate calculator is somewhat good for coming up with a ballpark number, but it does not take into account a lot of variables that make a significant difference. It paints entire states, or at least large sections of entire states with the same broad brush, ignoring soil types, hybrids, in season wheather changes, and yield potential in general.
I've done replicated strip tests where higher rates of in season nitrogen applications showed positive economic returns, even in 2020 when the crops burned up due to heat and lack of rain from late June to harvest. It was not a huge difference, but I really have to question the validity of that calculator when it is far from being site specific.