If you would like to tweak animation timings after using the Sync Animations tool without having to redo the synchronization process, you can use the Audio Editor to fine tune your animation timings.
After setting your animation timings using the Sync Animations tool, Save & Close the Sync Animations window. Then launch the Audio Editor (Articulate > Audio Editor).
Using the Audio Editor, you can drag individual animation markers left and right along the audio waveform to make very precise placements. To learn more about using the Audio Editor, see: Narration > Using the Audio Editor.