So after many test, here is what I noticed :
- if you refuel with more than 2700, no problem to refuel AAR or on the deck
- if you refuel at 2700 or lower, you will have the tanks L and R going to 0, with the warning lights blinking and only the main indication goes back up to 7700. The fuel flow is then twice as indicated and so you are loosing your fuel really fast
- if using the dump switches, they turn off at 2700 and you cannot turn them on to go lower. Maybe a bug, maybe working as intended.