just got a bulletin today at work and as of now ALL OPTI'S INCLUDING PRO XS ARE TO NOW RUN OPTI/DFI OIL AS THE RECOMMENDED OIL, i have seen a ton of compressor failures and most are on pro xs's??? not sure if the oil was the main contributor but besides that the dfi oil is a cleaner burning, less carbon build up formula, i know premium plus is a great oil but maybe they have put there finger on something??? just wanted to let you guys know of the change!!!!