Marc02
   Marc your 100% correct but some on this site doesn't want to hear that. You have to know basic refrigeration to trouble shoot an air conditioner. If you make a statement like you did or what I am saying we are going to be put down. At least one other person on this site knows refrigeration that I have observed . A fellow with Jersey in his name. I have gave up on posting on A/C problem listed on here and looking for help because of that reason. I spent 2 years in a very good Refrigeration Tech. school at Oklahoma State University with 2 super teachers/instructors.Then after 10 years as a service tech ,started my A/C business and ran it for 40 years.Passed it on to family members educated  in Tech school also. Constant schooling by A/C manufactures is necessary every year to stay current. New high tech systems are charged by laptop computers by Super heat .subcooling,load on the evaporators and ambient temperatures ,both inside and outside temperature.
NOTE::: IMHO This is because too many installers were clueless on the  refrigeration cycle.
   Also why do some object to hiring an A/C technician that knows what he is doing.???
Good luck too all.