I just noticed something while working on a Melbourne qual setup...
I did my initial runs with 8L of fuel, which is just enough to show a
2 for the lap estimate. No problems, car started sputtering a little
midway through the first sector of my in lap.
Shortened the gears a tad and did another test. Fuel estimate did not
change. However, this time the engine started sputtering just after I
exited the final turn leading onto the front stretch.
As best as I can tell the lap estimate is a static figure, but the
actual amount of fuel used varies depending on engine speed (as it
should).
Jason