Dumbledore's pre-timeturner-talk is the last of the "what on earth is going on" moments of the book, I think. And it is another excellent example of it (Dobby-free as it is).

I think the time travelling works, although it is somewhat in contrast with the emphasis on the power of choice elsewhere. I think Dumbledore later on tells us that the prophecy could have been averted, and only became true because Voldemort acted on it. But the time travelling suggests a universe in which things are fixed and not subject to change through time travel. There is no proof that anything is changed in the time travel chapter -- to the contrary we have a very strong indication that it is not in that Harry sees himself cast the patronus, and another indication in that the sounds they earlier interpreted (again, interpretation in the context of prophecy is quite central) as Buckbeak's execution is now repeated with a different meaning, that is all.

Does that make sense?

For future books, we are told that ``The time may come when you will be very glad you saved Pettigrew's life'', which, yes.

And the ground is lain for the Quidditch world cup. I had forgotten that.