Headphone output power difference for UR22 MKII and UR242

Is there a difference between headphone output power for UR22 MKII and UR242? Since UR242 is not bus powered I thought there would be some difference.

yes, something about 1.5mW vs 3.75mW. UR22 MKII cannot drive professional headphones like e.g. AKG k-702 or similar.