It keeps track of when a feed was last fetched, but it isn't used for anything at this point. It does, however, cache feeds for 2 hours, so if the feed changes that rapidly, it may not update. It trys to use 'Smart Caching' to where it will detect if the feed has changed or not, but that is assuming that the feed is set to send the proper headers. When I get home from work, I'll post some code you can use to disable the caching to see if that helps.