Feed Article Versions and Updates

Sometimes certain feeds will feed the same article with the same title, but slightly different teasers and different links that will point to different updated versions of the article. Example;

http://biz.yahoo.com/rb/081001/business_us_financial4.html?.v=1
http://biz.yahoo.com/rb/080930/business_us_financial4.html?.v=13

Is there anyway FeedAPI can identify the article based on just the title and the feed source, and update the article link and teaser instead of creating another node for every published version?

How does FeedAPI update the feed items? Based on title and what else?

BTW, when FeedAPI does update an article it will throw away the publish date originally given to node->created and will overwrite it with the update date, which is a bug.