My Buick Century 2002 will be ready soon for the oil change. I have 55000 km ( 34000 miles) I am using dino exclusively. I have Petro canada Supreme 5w30 in the crankcase.I will have around 9000 km or 5500 miles of highway ( 90%) on the oil that is going to be analyse be Wearcheck.I'm going by the oil life monitor. I facing a dillema, should I now use Can Tire semi synth 10 w 30 ( Shell is supplying with very similar tech.data sheet) or should I use regular Pennzoil 10 w 30 in summer ??