Sitting-in the draft conserves 30% of your Power

Just confirmed that sitting-in the draft conserves 30% of your Power. Here is a graph of an interval workout I did last night where we (Jason Wood, Todd Wiley and I) were averaging 25 mph. (Well, at least they were averaging 25 mph the entire interval) You can see where/when I was sitting-in drafting at the 180w avg. line, and when I was out-of-the-draft, I was producing 250+w avg. line. (Same speed, same bike position.) Pretty cool stuff..only able to be confirmed with a Power Meter..in this case my iBike Aero.