ok what is the actual fault?
ceized compressor?
leaking evapourator?
leaking tx?
drier gets replaced when compressor is done to have warranty but usually when you replcae the drier we recommend you replace the condensor which is infront of the radiator (removal of bumper which is about 1.5 to 2 hours ) to replace the evapourator you need to remove the entire dash board, center console and heater box which takes between 4 - 7 hours depending on how mucn of a PITA it is being!
have the done any checks of any sort ie with a/c guages? temporary regas with leak detectant dye to locate any leaks?
ef & el falcons are prone to leaking condensors along poor welds on let end tanks when we replace the replace the compressor & Drier as well, because of the change in a/c perfromance which if you don not replace the compressor you risk compressor failure which brings you back to square one because of debris being pumped around the system at my
work we charger about
1200 i think i cannot remember but thats aroundish
for a condensor and compressor replacement.
evappourator and compressor will be around the 1500- 1600 because we would also replace the condensor to avoid any comebacks. it is strange they want to replace the tx valve. we generally clean and re fit them. unless they have been working incorectly or look shabby we then only replace it.
to have the system flushed should really only be done if compressor has failed and there is deffinent evidence of deris.
i find it strange that they havent mentioned replacing the condensor as they cannot be flushed due to the fact they are parrallel flow ie have end tanks. debris will sit any where in them and if you cannot pass flush through them they will not ever be clean and eventually will cause failure of the compressor
any ways this is my opinion only but i believe you are being taken for a ride because they do not seem to have a idea of the type of a/c system
cheers!