When I need 16-18 gallons I stop at like 15 and shake the car. I've had this car need 2 more gallons before. I got in hit the start button and the gauge didn't make it up to the F. Turned it off got out and put more in. So I started doing it every time. That said I drive 100-130miles each day and the gas tank doesn't stay topped off; in other words I wouldn't want to top off in the cool of the morning and drive it 1 block, park the car and let it warm up 10-20°F while I work 8 hours. That would cause the expanding gasoline to get pushed in it's liquid phase to a canister that is meant to take in fumes as the fuel heats and expands.
I've filled my '14 Altima 94 times in 92,000 kms. I top it off every time. Sometimes as much as 7 liters, which is nearly 2 gallons. I haven't damaged the car by topping it off, and it makes such a difference to the range you can travel on each tank, so I'll continue to top it off.