There aren't a lot of written guidelines on this, but in my opinion POS 23 is strictly for services performed in the emergency department. If the patient is transported to the OR, 22 is more appropriate. The POS become inpatient once an order is written by a physician to admit the patient to inpatient status. Prior to that time, the POS would still be outpatient or emergency, depending on location.
Either way, these are all facility locations, so it will not affect the rate that the physician is paid for the same service. However, individual commercial payers process claims differently and may have specific guidelines for this because the benefit levels can differ between emergency vs. non-emergency or outpatient vs. inpatient services, so you may need to work with the particular payer to ensure that this is coded and captured correctly to ensure that the patient receives the correct benefit.