Debbie - in my experiences - and I have many "category" pages that rank #1 for their niche or at least in the top 10 for highly competitive phrases - the difference should be around 15-25%, not counting the outgoing links - if you have around 200 or so links out going and a good amount coming in the percentage can be a little lower.
As far as Googleguy - yes he is real - he is a self described engineer that works for Google and most think he is Matt Cutts - he has a blog here:
http://www.mattcutts.com/blog/ where he describes his responses to different types of schemes and SEO tricks