Upon further review...

Don's math skills have been called into question. Grant that he hadn't really slept in more than a day, and was exhausted on a beach trying to scrawl on paper balanced on his hand...but...the clock doesn't lie, and we started at 6:45pm and finished at 2:35pm-ish, so he must've mis-carried a one. Our total time was definitely under 20 hours...yay! -Nathan