If the orifice tube is plugged up then it's likely that you have had a compressor failure and the whole system needs to be flushed and the compressor replaced. Do you have any pics of the orifice tube that you pulled out? If there is a blockage then it should be fairly visible. What I find strange though is that you say the pressures were where they are supposed to be which would be the case of there was a blockage. There is also supposed to be a temperature shift at the location you noted, it's normal.