Well, thats how "calculating" and "doing" differ, I guess. Might be worthwhile to take a step or three back and see if you can reproduce the values used originally.

Things like head, flow volume, etcetera.

It could simply be that some prior "expert" either miscalculated or was not much of an "expert"

Quoting like you did leads me to believe that person was inexperienced.

I am no expert in anything but that looks like something a college professor would write up rather than saying "23KW of energy is available".

Its your baby so do what suits you.

Tom