Performed preventative maintenance on system. Changed out filter for customer. Inspected all equipment. Washed condenser coil thoroughly. Customer said system is cooling but not as well. I checked thermostat operation, wiring, capacitor, contactor, compressor, fan motor, pressures and temperatures. System is a little low on refrigerant. I added 1.1lbs to get system back in range. Last tech made suggestions to change evaporator coil. Went over that with customer. Coil may have a possible leak. As of now system is cooling properly.