Using FeedAPI for maintaining product pages from XML Feeds

Hello.
I want to know, is it possible to use FeedAPI for affiliate site ? I need to update product information from external XML feeds but there may be issues with updating existing entries. Is it possible to update existing product node using module options ? I see there is some complicated logic about duplicates and expiration of old items...

Am I right in guessing it is possible to expire old product entries and just create new ones on cron run ? But possible use of "Delete news items older than: " option is not clear, because cron can run, say, every 15 minutes but the minimal expiration time is 1 hour