Question: when you synched your anims to your narrative, which approach did you take?  Did you use Synch Audio from the Presenter toolbar, or did you try to use the Edit Audio dialog box?
 
Rob

That's probably due to an artifact of working with the Audio Editor.  There is a known "bug" such that if you change the view by which you're looking at the waveforms of your audio (by using the zoom in/zoom out controls), it will actually change the placement of the waveform in the dialog box.  And because of that, it will most likely mean that your animations are not completely set up to run at the time you expected them to.  Bottom line: if you're not "zoomed in" enough, you will encounter some "slippage."
 
Also, I would strongly recommend NOT recording audio using Presenter's Record Audio function.  There have been a lot of folks who have reported multiple problems...and honestly, if you ever run into a scenario whereby you need to tweak your audio settings, Presenter does not have the capability to edit audio files in the same way that you can with other tools...like Audacity for example.  And because Audacity is FREE, it's a no-brainer.  The other advantage of using a separate audio source is that if you have to re-record your audio, it's just plain easier to do so outside of PPT/Presenter.
 
Rob