Some airlines even use that during replanning (typically redistpatch in flight) so that once in flight and withinless than 6 hours to arrive they can eliminate the alternate fuel requirement. I assume they add the 15 min...
Absolutely, not only makes it sense but it's also economical and probably the most efficient way to save fuel on long haul flights. The idea is pretty simple and brilliant at the same time: land with about the same amount of fuel in the tanks after 14 hours flying as after a typical mid range flight, say within 6 hours. It's just a way to reduce a proportionate to flight time amount of contingency fuel to a reasonable end amount by placing a en route re dispatch airport typically within the last quarter of the total distance. In the end it the same whether one lands with 6 tons, 330 let's say, after 5 hours flight or 14 hours.
