Update: I went to Estern CAR AC for your recommendations without any delay. Eastern CAR AC check the issue fully. They checked my compressor, your stock compressor is 100% working fine. No problem at all with compressor.
Only Full service and checking for gas leakage are required. They opened glove box, took out the blower and evaporator and when I saw these two, I amazed with dirty condition of both of these. After inspection, they said that expansion valve is good, no need of change it.
They cleaned whole AC Components including condenser and it fan also.
New Dryer bottle has added with pressure switch with new condenser fan motor because previous one is very slow.
At last, they filled oil in compressor according to requirements of ac compressor and filled the gas in compressor.
Now cabin is very chill and temperature in cabin is reached around about 8-10 C at even low rpm and idle state.
But for better cooling, they take out one of heater pipes from engine hose. I don't know where these pipes are located?
When I asked them for this, they said, SIR, Hot air may be mixed with cold are and there is slightly difference in cooling occurred. They said me when winter will come, go to any mechanic and tell him to connect the heater pipe, he will connect that heater pipe and heater will work like charm.
Now @xulfiqar and @racerali tell me that removal of heater pipes can be harmful to engine, heater or not.
Is any damage occur with removal of these pipes?