Doing quests that are over your level should net more xp than doing them at level.
This would encourage overpowered TRs to run quests at the highest difficulty that they can handle, rather than running quests that are 2 levels below their current one.
So for example if at the moment we would see level 7 overpowered TRs running level 5 quests on elite for bravery bonus, under the new concept we would see them attempting to run a level 11 quest.
resulting in a more challenging and enjoyable game.