AIR DOES NOT GET COLD WHILE GOING SLOW WHEN YOU SPEED UP IT DOES GOOD

My 2007 Ford 500 is doing close to the same thing. When idling or stopped the air will not cool. Once driving and picking up speed the A/C cools fine. It is in the shop and is going to cost me $898.00 plus tax. My mechanic is replacing the compress, expansion value and dryer to correct the problem. He first told me all he had to do is replace the dryer and expansion value. However, as you can see now the compressor has to be replaced. I question the fact why he didn't test the compressor before he started tearing into it. Maybe it's not possible on vehicles of today. I don't know but seems like it should be possible. Oh Well, This frustration makes me question whether I will buy another Ford in the future. I'm just not sure.

Been seeing this problem a lot with the 500s. Most answers that I have found is that the RCV needs to be replaced. (around $30 for the part)