Ah, I think I may have found the answer to my own question...
Apparently, during takeoff the flaperons enter 'bypass mode', whereby hydraulic pressure is removed to prevent fatigue to the actuators. This causes the surface do droop under its own weight. As the aircraft accelerates, aerodynamic forces cause the flaperon to slowly lift until it is flush with the wing. Above 80kts, hydraulic pressure is restored and so the flaperon returns to its 10deg droop.