I did work it out... The spreadsheet he sent actually has the correct equation embedded in it. So I pulled it out, translated the Excel codes into the different variables, wrote out notes explaining to myself what the variables are, and discovered that he hasn't sent me the table of orifices, so I can't finish this stupid equation anyway.
Actually I'm pretty proud of myself, because I can follow this stuff, more or less. See what waaay too much college math does to a girl?
Eventually gets her better pay than the ones who don't know the math! I am proof of that!
Caution, taking a teaching job severely messes up that pay thing!