One more thing: The author doesn't start receiving royalties until after the book has earned out its advance. So if, hypothetically, the author was paid an advance of $10,000, they don't see a penny of royalties until after that initial $10K is paid off. So, in your example, the author would only get $26K in royalties since they were already paid $10K in advance.
In general, your advances are what you count on. Any extra royalties are gravy.
Meanwhile, I believe Peter David is the most prolific STAR TREK novelist.