Actually, the 1HKO and 2HKO odds are perfectly accurate. In the article (http://www.smogon.com/dp/articles/damage_formula) it does indeed say the following:
"85, 87, 89, 90, 92, 94, 96 and 98 each have a 7.69% chance of being chosen.
86, 88, 91, 93, 95, 97 and 99 each have a 5.13% chance of...