I think thats when you basically use your points for each day and then add up to a weekly total and then split them for high pointed days and low pointed days throughout the week. It was designed to shake up your metabolism and boost weight loss. I'm not quite sure if it works though.
The Noreen Blackett page has a good idea of how it works and the link to the official plan My Long and Bumpy Journey | A new me in 2007