I have found I have to multiply the FOB by 2.5 in order to make sure I can get where I'm going without running out of gas.  And CS has made it so we can add more than enough fuel to make the realistic range of the 767.  If it were Microsoft Flight Simulator X I would adjust the fuel flow, and the fuel burn.  Captain Sim, if you're listening, please work on a patch that adjusts both of these for the 767-200/-300/-400.  Thanks!