gas gauge reading when full but goes down quickly

I'm not going to argue the difference in the float arm length.
Draw 2 clocks, a box clock with a pendulum window 12 inch square, and a grandfather clock with pendulum window 12 inches wide and 36 inches long.
Recon both clocks would keep time ? I think there would be 60 swings per minute in both LOL Back to the senders
The arm stops and that first 1/2 inch or so of the arm that hits the stops, along with distance from bottom to top of tank, all constant and unchanged
Yall believe what you want to believe.