Lin, Lin, At first, I puzzled over the effect of non-linear speed criteria at specific keypoints, too. But after exploring the "setting up" option, the problem became non-ambiguous: the interval between two labeled keypoints is bracketted, so your selected speed option appleis to that entire bracketted interval. So, if you have three keypoints, you can have two intervals (each with its own speed option). So after my initial immobility, the above realization allowed me to get moving :>) Best wishes, David White (frets3)