This sounds within the proper spec. Some AC systems do blow colder but mid to low 50's out of the vents is acceptable.
Plus the pressures that you are seeing are within range as well assuming the temp was around 75 degrees when you were doing this test.
Take a look at this chart for pressures and make sure it lines up.
Let me know if you have questions but I suspect this is okay. Thanks
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Monday, March 30th, 2020 AT 3:09 PM