Compressor Is Always Running

I just had the evaporator on my '97 Tacoma replaced. The mechanic added 3oz of oil and 20oz of 134a. I am concerned that the compressor runs constantly and does not cycle every 20-30 seconds as I recall it used to, though the temperature here hasn't dropped below 85 degrees since the repair. The temperature in the vents is 50-55 degrees when the ambient temperature is about 85 degrees. The sight glass never gets clear, just lots of bubbles - but that may also be due to the high ambient tempeature. Clutch disengages when AC switch is turned off as expected, and clutch was disengaged until initial 134a recharge brought pressure up - so the pressure switch near the Expansion Valve is working at low pressures. Is it working correctly now or was it working correctly before. Also, if the mechanic didn't evacuate the system well, what would I notice about its operation.