"thrown ap" is found in vanilla and I have heard views that it is the same as "thrown, ap" - but this needs testing.

What does seem to be true is that "thrown" has a reduction in time between volleys and that it comes into its own when it goes against opponents with multiple HPs as it seems to gain some sort of bonus against the same.

I have not personally looked into this too much but hopefully xerex/aradan will test it out and update the EDU Guide on this matter.