Not quite-

Did you drain the tank from the sump, or from the line? The Super Cub
is supposed to have 17.4 gallons usable, 18 gallons total. If drain it
from the sump, and fill it, you'll put 18 gallons in. If you run a
tank dry, you'll put 17.2 in. If you're running at a low cruise, that
1.6 gallons you don't have is 20 minutes of fuel that you were counting
on.
..