I would say yes, or Boeing would have a note in the QRH. "Flaps Drive"on a heavy T/Off, thats a long wait to get back to 285,000kg for a return. If not and something else nasty was happening, land overweight, but again knowing how Boeing designs checklists, if it was a problem they would tell you. Interesting question though. Due to time contraints all my Sim departures have been not above 285 ton, any dumping uses up too much time. They love to fail the outboards leaving that nice pitch up tendency.