Google must be making some changes.
Update: From the Google Reader Blog – “These numbers include subscribers across all Google services, including Reader, iGoogle, and Orkut. You can see them in Reader’s feed search results (pictured below) and the Google Webmaster Tools. Additionally, our crawler reports them to the publisher each time we fetch the feed. Reader’s feed search was recently showing stale and incomplete data, but as of today (October 15) the numbers should be the same everywhere.”