True Position vs Location Xact Measure

So when using the True Position feature in Xact measure, PCDMIS builds its own trihedron. If your using a iterative alignment the two trihedrons do not match, the trihedron PC DMIS builds is to the part. Does anyone else run into this, and if so, which one is correct to use on parts. Im thinking that the location dimension must be location in the car and True Position must be the True Position to the print.