CST - Far Field Source Units in CST

I exported a far field source out of a simulation for an antenna. The units for that model/simulation were in millimeters. I imported the far field source into a reflector project, and simulated it. The reflector project is in inches. 

 

When I look at the phase center, it is bad sigma (wide variance) in my lower frequencies.

 

Question: Does CST automatically convert units for a far field source, or does it ingest as the units that are imported?

 

CST Studio Suite