The flap csu provides direct input to the flight control system and adjusts the gains according to lever position. Is also why the csu has a breakout function if jammed. Ref the report from vr-hyu in hkg many years ago.
The Kinematics figure shows that a 5°/sec side-stick demand in Config Full results in aileron and spoiler deflection of approximately 11.5° and 3° respectively. The same side-stick demand in Config 3 results in deflections of 18° and 8° respectively. Clearly the aircraft is more sensitive to control inputs in Config 3 than in Config FULL