Upon arrival client stated that unit was cooling at 7am at 62 degrees, client turned unit off for about 30mins and the unit was struggling to keep the area cool. We proceeded to check temps of the room and coming out of the unit. We proceeded outside to check refrigerant pressures and found that the unit was about 12oz low. We added the 12oz to the unit and unit started to stabilize. While adding refrigerant we also measures the RLA amps on the outside unit to ensure the proper amp draw and Freon pressure. Unit was cooling properly upon departure. 48 degrees was coming out of the supply head. We did also discuss option to start with a virgin charge that would involve a full system vacuum and weighing in refrigerant to manufacture specifications. Client is aware of this option and declined due to potential cost associated with it.