POS 15 - Mobile Unit (physician on wheels)

Hello,

If a physician is asked by a company to do "preventive screenings" to company employees only, company would provide a empty office space to see the employees, would POS 15 be appropriate to use? If yes, what would be the name of the facility on a HCFA 1500 claim? Would it be the Provider Office Address (where medical charts are stored) or would it be the actual name of patient's employer address on the claim?