FE Hoppy
Point well made and taken
However, as with most things to do with aerodynamics, unless one is working as, or training as a TP or TE/Obs, most average 'Joes' want some sort of 'simple' visualisation of the more abstruse areas of these functions.
I'm reasonably sure that the difference between MAC and MDC is not going to overly exercise most new RHS occupants but a reasonably simple mental picture is usually 'close enough for Government work'.
