I tried having a long haul and used SimBrief for the planning.
SimBrief calculations and the flightplan showed that should carry 19hours 40 mins of fuel, but the maximum capacity of the 777-200LR in IF shows a Max Time of 18 hours 19 mins.
I further searched for the maximum capacity of the actual 777-200LR and it has a capacity of 195,285 L. However, again, in IF, the 100% capacity is 147,576 Kg, approximately 125490 L.
So is this a glitch or a problem in the development? And can it be rectified by the developers?