Hi folks,  

  I am struggling to report a Composite Feature Control Frame for true position of a hole.  The upper frame controls the hole position to A, B and C.  The lower frame only controls to A datum.  The hole itself is perpendicular to A datum surface.  All of the examples I am finding on the googles and internets show the lower frame containing two datums.  For example, ABC in the upper and AB in the lower.  It seems to me this should actually be a single FCF for true position to ABC with a separate FCF controlling perpendicularity to A datum as I don't see how a bore perpendicular to a surface can control location.  

Any help is greatly appreciated.  I'm a machinist recently turned CMM Programmer.