My wife just purchased a 2015 Mazda CX5 Grand Touring with the 2.5 that has about 5700 miles. The owners manual calls for 0-20 in the U.S. and Canada and 5-30 everywhere else. According to the sticker in the windshield, the selling dealer filled it with Valvoline 5-30. Do I dump the 5-30 and fill with 0-20 or run the 5-30 for a short OCI? Going foward, use the 0-20 or 5-30 or will it not matter at all?