What do you guys think about a spilt carrier straight cool, that has been vac and micron gauged, with a weighed in charge put in, but only has a 10 degree split at the evap coil? Subcool was ~40 degrees with ~8 degrees superheat. I tried to purge the unit to lower the subcooling to 16 then to 10 then 6 degrees but has no effect on the temp. split. No restrictions in filter drier, so does it have to be the TXV or is there another option?