Mixed Messages on Site Cached or Not?

Earlier today I replaced WP SuperCache with W3 TotalCache. It does seem to have improved performance and my site’s source code says stuff is being cached:

Page Caching using disk: enhanced (Cookie is rejected)
Database Caching using disk (Request-wide Cookie is rejected)
Object Caching 3363/3968 objects using disk

Page, database, object and browser caching are all turned on, but the site I use to measure performance is telling me I’m not caching stuff:
http://www.webpagetest.org/result/130916_FB_11A4/1/performance_optimization/#cache_static_content

I’m tempted to trust the plugin and ignore, but want to make sure I’m not missing something. Any ideas for things to check?

http://wordpress.org/plugins/w3-total-cache/