Part of RSRD. As we know, filling 15000 gallons of fuel does not happen in a minute. So, as part of realism, this was added as the average time for refuel. I normally do not TC for 4 hours. I just blast out of port.

Does it effect game play? Just might. If you wait those 4 hours you just might hit that convoy coming at you. If you just go after the refuel, you just might blow on by that convoy. Chance meetings all based on time. The choice is yours.