Wing bending relief is a bit of a catch-all. It covers active ailerons, fuel loading/burn sequences, pod-mounted engines, tip tanks etc.
In effect it can be thought of as anything that allows the wing to utilise that which must occur to allow lighter structure. Things like burning fuselage tank fuel first, outboard wing tank fuel last, loading wing fuel first, fuselage fuel last. Pod engs get unavoidable weight outboard where they help to oppose the lift forces. Lighter structure is the guts of it - less structural weight allows more payload.
Am I making sense for you FuelFlow???
