I hope they did not charge you for each visit.
you say the tech checked pressures. But did the tech also check superheat and subcooling. That is the only true way to tell what a system is doing. A 20 temp difference. Where was that taken? if it was taken at your return and supply registers, then thats a little high IMO.
I fully support the military and the War on Terrorism.
If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.
If you do know, then do. But do it right. Otherwise, you may not be doing it long.