Cad model nominals off by .03"

[[Bo...]]

I'm writing a program that has 4 symmetrical sides that get intersected and become a datum in the center of the part.  when i do this my actual's get shifted up by .03" in the Z direction from my base alignment which is also the center of the part.   I find the center of the inside of the part for my base alignment for navigation and then to proceed to measure the out side perimeters for my B/C intersection . 

when I check the cad model in solid-works all my sides do show to be symmetrical to each other. 

I have retried programming my sides and then create a symmetrical intersection but this does not help.

 

Any suggestions?