Under those conditions, a reduction from 35 Deg C to 10 Deg C in 1 pass through the evaporator, is pretty effective cooling. I guess the only real way to determine if the system is operating correctly is to connect pressure gauges and check that it is within specifications and the thermostat which controls the compressor is also operating correctly. It may just be the characteristics of the refrigerant.
Note, the fastest way to cool, a car which has been in sunshine, is to lower all windows and drive the car with AC on and remove the superheated air from the interior and AC pipes, then close windows and let the AC do it's job. You will waste fuel and work the AC harder, if you don't follow this procedure.