When was that book published? Remember that the longer ball pythons are kept in captivity, the more we learn about them.
The two most recently published books on ball pythons with the most up to date information are:
The Complete Ball Python by Kevin McCurley (of NERD) published 2005
Ball Pythons of the World Vol II: Ball Pythons by Barker and Barker (of VPI) published 2006
If you click the titles, it will take you to where you can order both books.
I trust the experience of the members here and my own personal experience. I keep my warm side at 92-94 degrees and my cool side at 82-84 degrees.