I would think overhead would be the 7.3% cited on Charity Navigator and the 22% fund raising would be separate. Maybe that 22% will really pay off in the future. If Bill likes them though they can't be doing too bad.
The proportion spent on fundraising isn't a good indicator of effectiveness either. Generally, the metrics tracked by Charity Navigator are easy to measure, and aren't very useful.
GiveWell is a much better evaluator of charity quality. Since they spend much more time on analyzing each charity, they cover way fewer charities. They are quite strategic about prioritizing which ones to interview.
http://www.givewell.org/international/process