The thrust calculation has a CL coefficient of lift. Propeller pitch has an effect on this CL term, as well as airfoil shape, and chord width. None of these factors exhibit a linear relationship with the coefficient of lift, that's why basic calculation such as ThrustHP doesn't bother including them. To obtain an accurate relationship between coefficient of lift and airfoil, chord width, and pitch, experimental analysis needs to be conducted to form an elaborate database. Only then can we better "approximate" the thrust result of a given prop & rpm.