A great post. I have a few comments though
1) She comments that she has not earned out her advance yet and once she does, she will get passive income from this book in future years. So, if you start at Year 0 with a best-seller your annual income will be low, but then in future years, your income will be advances from the new (which she said was about 50K) plus royalties on former books. She mentions this is book 8 in the series. If she earns just $1000 a year in royalties on each of these (assuming a spike in the backlist when a new volume comes out then that is almost 10k a year of passive income. Her 'salary per book' will not be known, theoretically, until she dies, so if you look at 'income per year' instead, it will be more than the 25k she mentions since it will include royalties on her past books. So the picture she paints of her annual income here is not totally accurate.
2) She sold in the vicinity of 80,000 books and make about 25k. That's about $3 a book. Let's say she cuts out the publisher altogether and sells on Smashwords for $5 a book. She gets 85% of that, so that's $4.25. To make the same 25k, she'd have to sell only about 6000 books. If she sells just half of the 80,000, that's $170,000 which is way more money even if it is fewer copies. So an author who is smart at self-promotion and gets a good rep can do a lot better as an indie, it seems.