You can do this protocol using a neutral, wide, or underhand grip. I like to use a different grip each time to create a different stimulus. The isometric is performed at the bottom position because this is the point of the ROM where most people cheat.
If a trainer were to come to us and say he had a method of ab training that would reduce the waist size of anyone in three weeks, we'd ask him what he was selling and then kick him out the door. Luckily, Don Alessi was a fast talker and before we could introduce him to the sidewalk, he'd convinced us that he had some pretty nifty ideas.