People who live in high altitude regions, e.g., Colorado, may be running less than 87 since less than 87 is routinely sold as Regular. For most older, dumber, cars, the car would never know or care about running 85 in place of 87 in Denver. There's some question whether this is still true. Honda is silent in the OM. Ford, in the manual for our former '12 Focus, explicitly said to use at least 87 even in high altitude areas where lower octane is sold as Regular.