Replacing alternate freon after loss of capacity.

This morning's job, I should give a little background on what we're doing. The compressor was changed, the evaporator was changed, and I was called out here because of a home sale inspection that said we had a low temperature drop, and we did. The best I could get was 10 degrees, and after about an hour of troubleshooting, I found that i had high head low suction high sub cooling and low super heat um this is an r22 system but i could not verify which freon was in it totally i think it was all 22 i mean that was the closest i could come to but um i did not think it was the txv i think it was the freon giving me troubles i had about a 30 to 40 percent capacity loss and it was not because of a dirty coil i mean it's a little bit dirty but that's not my reason i believe my reason was my freon so i recovered the freon we're pulling the vacuum and we're going to recharge this with um virgin r22 i'm debating how low to go with my vacuum this system was never open to the atmosphere i'm just wanting to remove all the old freon shooting for 500. i already have pressure on this i pulled down to 500 it took me forever because the system had a little bit of oil trapped freon in it so we are fixing to start this thing up charge it it takes 8.31 pounds 133 ounces i think it was and um see if it does better if i get better pressures and whatnot i said factory charge was 8.3 pounds and i got about a 50 foot line set so i'm expecting at least nine pounds target sub cooling and super heat gin i'll let all this liquid get pulled in and we'll look at pressures again most where i need to be i've got a 15 degree super heat 10 degree sub cooling i am almost where i need to be i'm gonna charge this up and then we can do a temp drop the last one i was just on that has the The problem with the Freon, I couldn't get video inside, but I was able to verify that I got a 15 to 16 degree temp drop. Proper sub-cooling and superheat our pressures were fine, so I don't know if that Freon had been mixed with something. But pulling that out and replacing it with R22 fixed my problem. That's 22 like that, so I think there was something else going on.