Composite True Position

[[Du...]]

I have this position callout on a drawing, its for a set of 8 holes, top section is in tolerance but the bottom section is out of tolerance, I can't seem to wrap my head around what the bottom section is actually controlling and what is out of tolerance. 

 

[[RP...]]

https://portal.zeiss.com/knowledge-base?id=410967

[[Ch...]]

A few additional KBAs on the topic as well.

CALYPSO: GD&T Engine: Simultaneous Requirements
CALYPSO: GDT Position >< Direction Only Evaluation

[[Ch...]]

Read thru ASME Y14.5-2018 starting on page 214.   It has some good examples similar to this.  

[[Be...]]

Let me give you a 1-dimensional example.  Suppose that the callout is for the 1" and 2" tics on a ruler.  Datum A is the face of the ruler that would touch the paper.  Datum B is the end of the ruler.  The upper control frame controls the distance of both tics from the end of the ruler.  The lower control frame just controls the distance between the two tics.  The 1" tic could be 1.5" from the end of the ruler and the 2" tic could be 2.5" from the end of the ruler.  In that case they would fail the upper control but pass the lower control.