Sitemap not displaying everything

Hey,

So I am new here and making my first post! Excited about all the plugins available and integrating them into my WPMU sites. Having some trouble (or possibly just don't completely understand) how the sitemap plugin should work. First off my website uses subdirectories, not domains. My question may be that I just do not understand how the sitemap works 100% but here is what I believe to be my problem.

Everything seems to be working fine, as you can see my site maps are being generated here:

http://www.rantsports.com/sitemap.xml
http://www.rantsports.com/mlb/sitemap.xml
http://www.rantsports.com/nfl/sitemap.xml

But I have way more content than is being displayed in the NFL and MLB sections. There are well over 1,000 posts, and a few pages in each. I may be wrong, but shouldn't they all be displayed in the sitemap?

Like I said, may just be that I do not 100% understand how a sitemap works but any clarification would be great!

Thanks,
Grant