I need assistance. I am confused as to how to differentiate which POS is correct to use when billing E/M codes – Office or On/Off Campus – Outpatient Hospital

The physicians are part of a Medical School faculty which is associated with a Hospital. They see patients (E/Ms and office procedures) in an outpatient clinic space owned by the Hospital. It is in the same building as the hospital.

CMS defines the On Campus – Outpatient Hospital location as: “A portion of a hospital’s main campus which provides diagnostic, therapeutic (both surgical and nonsurgical), and rehabilitation services to sick or injured persons who do not require hospitalization or institutionalization. (Description change effective January 1, 2016)”

Campus is defined as: "The physical area immediately adjacent to the provider’s main buildings, other areas and structures that are not strictly contiguous to the main buildings but are located within 250 yards of the main buildings, and any other areas determined on an individual case basis, by the CMS regional office, to be part of the provider’s campus."

Office is defined as: "Location, other than a hospital, skilled nursing facility (SNF), military treatment facility, community health center, State or local public health clinic, or intermediate care facility (ICF), where the health professional routinely provides health examinations, diagnosis, and treatment of illness or injury on an ambulatory basis."

Is the fact that the space is owned by the hospital and in the same building indicative that it is therefore "part of the hospital campus", and should be entered with POS "On Campus – Outpatient Hospital"?

Or does this clinic space qualify as a Location, other than a hospital and therefore gets entered with POS "Office" ?

How do I know when "Office" is correct to use or "Outpatient Hospital" is correct to use?

Any insight is greatly appreciated.