Hi Morgadeshou,
You're completely right about those estimates, it seems that around 0.57c per word is what most people are expecting based on last month's pool. Amazon usually add bonus funds to the pool, so it may jump up a little.
I've read some of the discussions myself now, and you're right, for the full-length books, there's an opportunity to earn more than a buy.
I thought the move was designed to discourage the 30-page scamphlets, and it should do a good job of that. My books are similar in length to yours (I saw the KENP figures added around 25%), and it looks like I'll be hurting from this, though.
Previously, borrows were $1.35. Assuming the estimates are correct at $0.0057 per word, multiplied by the industry average 60% read-through rate, I'll earn around $0.50 for a 150-page book. If the rate increases to 1c/page, it'll be just short of a dollar, which is not a complete disaster. I produce series, so I'm guessing the readers who check out my other books do so because they read the first book in full, in which case I'd earn $0.85-$1.50 per borrow.
I've read a few conversation threads on different forums, and one person pointed out that just because a book is short, doesn't mean that it's low quality. I agree with this, but the changes are designed to hurt the scamphlets, and I think they will be successful at that. There seems to be a lot of kickback from the community, so perhaps they will improve the distribution model over time. With my narrow-focused non-fictions, there's just no room to produce 800-pagers, but it doesn't mean my books are less valuable because of this.
You're right about the final point. The funds are staying the same, so it's just moving the money from the short book authors to the longer ones, rather than into Amazon's pockets. And I don't begrudge authors who write 400-page novels earning more than me per book.
Even though I might be hurt in the short-run, I'm still all for this move. Anything to prevent the low quality books from winning is a good thing. They really were killing the platform. As I mentioned before, the move might make the marketplace less competitive, and therefore any quality books you've produced may start to perform better.
Borrows aren't everything either. I made about 30% of my income from borrows last month. If my borrow income is halved, I'm only down 15% overall.