DataFeed historical versions

Hi there,

   I have an api call that needs to run regularly (almost like polling), but I need the ability to begin at the point in time that the last record's datestamp. The gaps between runs are not constant, so I am storing the fromVersion value in the database and doing a lookup to get that before making the next call.

My problem is that I'm not getting predictable results - like only one most recent record.

Am I trying to do something that's not possible?