Do you make a habit of monitoring your frames per second when viewing playback in Motion. In the Status Bar during playback there is a FPS value being displayed. The frames per second or FPS tells you how close to real time you are playing at. It is easy to think your timing is off if you don't notice that your FPS has dropped down below 17. Heavy compositing will cause low FPS. At this point a RAM preview will allow realtime viewing. If you don't have any audio it is easy to not notice that you are playing at less than three quarter speed, which is why it is a good habit to constantly monitor the FPS. If your FPS is not displayed during playback, there is a box you need to check in the appearance category of the Motion preferences.
