As the video, 100% fuel cannot be loaded, 99% is fine.
Aircraft: COWS DA42 series
Here are the relevant Fuel parameter in the flightmodel.cfg.
LeftMain = -4.37, -11, 0.4, 25, 0
RightMain = -4.37, 11, 0.4, 25, 0
LeftAux = -6.24, -5, 0.4, 13.2, 0
RightAux = -6.24, 5, 0.4, 13.2, 0
fuel_type = 2
number_of_tank_selectors = 2
electric_pump = 1
engine_driven_pump = 1
manual_transfer_pump = 0
manual_pump = 0
anemometer_pump = 0
fuel_dump_rate = 0.00
default_fuel_tank_selector.1 = 19
default_fuel_tank_selector.2 = 20
fuel_transfer_pump.0 = 4, 2, 0, 1
fuel_transfer_pump.1 = 5, 3, 0, 2
fuel_tank_priority = LeftAux-RightAux, LeftMain-RightMain