In the real world we need 20 mins to travel to field B from field A. In AH we need only 5 mins. Acording to this, fuel consumption has been multiplied.
In real world we need 10 mins to climb to 20k. In AH we need also 10 mins. So, the fuel multiplier is affecting directly planes with an extremely poor rate of climb and a high fuel consumption level like 190A8 while not affecting at all planes like P51D, Ta or P38L.
Actualy, climbing in a 190A8 is extremely "expensive" and not climbing is extremely suicidal.
IMO, actual fuel multiplier factor is based only on distances, and it should also consider altitudes.