To be honest, it does not take a tahun to produce a film and ubah it. This is Summit's plan of trying to susu the Twilight Saga of what it's worth. However, this isn't the best plan, considering, the momentum of the series is slowing down. I mean, look at the Twilight series spot now. All the fansites. Hardly any news, therefore, fan become uninterested until things pick up again.
So in answer to your question, there isn't rally a good reason why they are releasing part 2 a tahun later. Splitting the movie adaption into two film might serve the story justice (we'll see), but releasing them a tahun apart is unwise.
The book was too long to make into one movie...they would have had to cut most of the story out....two movies...more of the story and lebih money for Summitt ....lol
Its there way of making lebih money, they are taking advantage of the movies because they are soo populer summit know people are going to pay to see it :)
I think they decided on doing them a tahun apart instead of 6 months because there are supposed to be a bunch of blockbusters selanjutnya summer. I'm not sure exactly what, but that was what the official release said.