I used about 16 mixers to make split elevons for airplane (4 servos total) - like this http://www.rcpowers.com/forum/showthread.php?t=3691 (my vid at the end of thread). Works OK, but when I tried to make airbrake assigned to switch - servos open like V shape, It didnt work. last edited curve changed itself to... to nonsense :) . I used 3 points for each curve, and they ended on one point, or on one vertical line, or endpoints moved somewhere in the middle, Only cure was to disable, save, enable curve. But saving didnt work after that, points moved again. I had about 180 points free at the time. I'll take pictures if I run into it again.