The paranoid motivation: prices are in tenths of a penny. Buying exact multiples of 10L is optimal in the sense that rounding is easily verifiable. Though, in Canada today, going $.02 past an exact dollar amount and paying cash beats out whatever games the station might be playing with tenths of pennies.
The gamer's motivation: most pumps I see have 3 digits past the decimal. Exact dollar amounts are easy-mode, exact volumes are hard-mode.
The gamer's motivation: most pumps I see have 3 digits past the decimal. Exact dollar amounts are easy-mode, exact volumes are hard-mode.