He spends most of the article explaining the jumping position and the up beat of the posting trot are one and the same. The exact paragraph reads,
"For obstacles up to 3-foot-6, your jumping position should be no farther out of the saddle than your normal posting motion. Done correctly, your position at the top of the arc is a response to the motion of your horse's back - rather than to you projectile-vomiting yourself up the neck of your poor, long-suffering horse."
You just have to see your distance...you don't have to like it.