I doubt there is a greater protein requirement for older athletes. Older folks have lesser muscle mass hence I would argue a lower protein reuirement for the same level of activity. The higher level of protein requirement mentioned in the article is due to the higher level of physical activity compared to an inactive person.
Here is an article with more specifics
http://www.infinitnutrition.us/libra...R%20MASTER.doc . Ryan deals with the issue very well in Sports Nutrition for Endurance Athletes (2nd edition).
Al