Perform non club tuneup to both systems. Washed condensers. Customer changes filters regularly. Blower and evaporator are clean. Drains are clear. Test all capacitors and motor amp draw. Test compressor amp draw. Refrigerant levels are in range for current temperatures. Both systems are cooling at this time. Found downstairs system to be a 4 ton system running at 880cfm of return. System this size requires 1600 cfm of air. Suggest adding another 16 duct return to system. Upstairs system also short on return air but customer does not use this system much and customer will consider work to upstairs unit. Gave duct price to downstairs unit. Both systems are cooling at this time.