your A/C mechanic is not competent, what were the gas pressure readings - and tell him to measure readings when this phenonmenon happens.
The problem will surface itself.
The correct procedure to service the whole A/C system is to wash with acetone, remove ac compressor and drain all the oil from it, put the system back together and add oil only as much as the yellow sticker says or the repair manual says. Then fill with correct weight of refrigerant.
Its not "andaaza" - Its a science.
