Authors, Writers, Publishers, and Book Readers
It appears that they have indeed deleted that page since I posted it back in May, Edward. Thanks for pointing that out. I found another take on this. Apparently there's no hard and fast rules, merely guidelines.
Edward D. Isenberg said:
The website page you cited no longer exists.
Try the vigorous and on-going discussion on Authors.com:
"How many words should a standard run of a mill science fiction book be???" at the URL: