I'm assuming it's there only to serve the interests of Corporate Average Fuel Economy, and it will get used about as often as the dusty buttons on your universal remote. (bestride.com)
The plus was a drive average fuel economy of 8.1 L / 100 km. (driving.ca)
This is the way of the world these days — small, boosted engines are designed to meet Corporate Average Fuel Economy standards first and foremost. (automobilemag.com)