I would like a feature where you can manually set the ramp fuel instead of extra fuel.
Rather it calculates backwards what the extra fuel ends up to given the options set for contingency, altn and taxi fuel.
For example lets say I chose to depart with 8000 kg as ramp fuel for a flight that requires much less to complete the leg:
Ramp fuel: 8000 kg
Trip fuel: 3000 kg
Altn fuel: 800 kg
Cont fuel: 150 kg
Extra fuel: 4050 kg
If the required fuel is greater than my manually set ramp fuel I will get an error. Much in the same way as today when required fuel exceeds max fuel.