Newbie here with a question about the green/blue bars in the dash display on both sides of the mph indicator. Just wondering if they're supposed to go back to green after an oil change. The owner's manual says they are indicators for good gas mileage. They were green when the car was bought brand new and went blue as the oil life decreased, but never turned green after the first oil change. How do you get them to back to green? No big deal but curious. At least they aren't pink or purple.