System on a mobile home with compressor shorted to ground. Replaced with the correct size comp for the condenser and before charging decided to remove and clean the evap. Upon inspection, discovered that it was a 4 ton evap that had been running on the 3 ton cond. Replaced evap with 3-ton coil and orrifice...weighed in correct charge...pressures weren't even close in cooling (25 suction and 50 head). the guy working for me assumed that his scales were wrong and continued adding r-22 until he got the pressures close to where they needed to be. unit worked well until....switched to heat mode and head pressure sky-rocketed..kicked out on hps....removed 6 extra lbs of freon and works correctly in heat mode, but low pressures in cooling (25 low and 60 high) I am thinking something going on with metering device in cooling....any suggestions, or am I simply missing the elephant in the room?