JD, see what you mean, and that makes good sense!
From those who do have a POH/AFM , I have heard many who still prefer or suggest rules of thumb instead of POH figures or, even worse, do not have a decision point at all... On the basis that it is not needed, or too cumbersome to do, or that the POH does not contain the data anyway... Therefore I wanted to illustrate that not only is it possible, but quite straightforward!