I had a chat session with @badp just the other day. Afterwards I noticed the following difference:
Does a mathematical relation exist between the two ((2*normal)+10...haha)? Is it a bug?
The number appears to be your total StackExchange network reputation rather than your WebApps reputation. Meanwhile, badges are only shown from accounts with more than 200 points. This is similar to the rules for Flair, except since you need a minimum of 20 points to chat I guess it counts them all.
See also this meta SO discussion.