HAVE NOTICED THE LUBE OIL PRESSURE DIFFERENTIAL DECREASING AND THE ONLY WAY CAN KEEP BARELY ABOVE ALARM STATUS IS BY LOWERING THE DISCHARGE PRESSURE. REPLACED THE LUBE OIL PUMP AND IT MAKES GOOD OIL PRESSURE BUT ONCE SYSTEM IS ONLINE AND DISCHARGE PRESSURE INCREASES THE DIFFERENTIAL GOES DOWN. HOWDEN TWIN SCREW MKIKSWRV16380361774. WITH R-134A REFRIGERANT. ALSO WONDERING, IS THIS A STANDARD COMPRESSOR OR A "h" COMPRESSOR AND WHAT THE OIL PRESSURE DELTA SHOULD BE. TKS