eWhisper - 9:34 am on Jun 8, 2013 (gmt 0)
Are you looking at one per click or many per click conversion data?
One per click is unique conversions; many per click is aggregate.
So in the above example, if someone goes to your checkout page, hits the back button, then goes back to the page - the user is 1 one-per-click conversion but 2 many-per-click conversions.
One per click is much more useful for many people; especially in industries (such as whitepaper downloads) where the final thank you page is often left open, sometimes refreshed, the browser is closed/reopened to the same page, etc.