Joe,
That checking of the freon is part of the contract I have with the company that I have take care of mine. They check that and all current flow, change filters,
oil and clean the Air mover and check the electric motor in it for current draw and check the belt. The outside unit they do the same for except it has no belt. He takes the covers off and oils the fan motor, checks current draw to a couple of big capacitors, and the change over valve, then comes inside and does temperature readings at the intake and compares them to ones at the registers to make sure they are within the normal range. And as I said before I have the added benefit of getting priority treatment in case of a problem over others that don't have a contract. Plus they charge me a little less by having the contract. They send me a card twice a year that it is time for my check, once in the Spring and once in the Fall.
Ron