''I fly the Classic (747-100, -200), and while the rudder does have a turn coordination feature, it's not active all the time; just when flaps are down.''
This is significant because the outer ailerons are active with Flaps extension and will consequently give more adverse yaw than the inboard ailerons. IIRC, (but it's 8 years and 2 type ratings ago) the 747-400s outboard ailerons are active from 236 knots regardless of flap position and this is when the turn co-ordiantion becomes active.