If you Top Off Your Gas Tank – Quit It!Deb HartDeb HartPublished: June 29, 2015Getty ImagesShare on FacebookShare on TwitterExperts say that once the pump shuts off after you've filled your vehicle's gas tank, there's no point in 'rounding up' to an even amount.It can actually damage your car and cost you money.Check out the details here fro the Detroit Free Press as to why you want to 'just stop'.