I have a 2011 4cyl Rav4 with over 70,000 miles and I want to start going to 10,000 OCI with synthetic. The car is out of warranty so I don't care about sticking to the factory recommended 5,000 OCI which I do feel is kind of a waste for synthetic. I do over 17,000 miles a year and it is 90% highway with no towing and conservative driving. My question is can I use my current mixture of oil (5w20 Mobil 1/0w20 Toyota/Mobil 1 Extended Performance 0w20/Amsoil 5w20) to 10,000 miles or should I just change it at 5,000 miles and wait till I can use the same brand and oil weight for the 10,000 OCI?? I know the oil filter is capable of 10,000 because it has the same filter as my wife 2014 Rav4 which is good for 10,000. I appreciate the input...