For example:
For one keyword there are 2 conversions and 3 sales.
On another site for a different keyword there are 2 conversions and 3 leads.
Why would this be? Is it because a user is reloading the page with the conversion code on?
They count a transaction as either someone buying a second time, or someone coming to your site, leaving, and then returning to buy at a later date.
Not sure how your definations on the conversions are set up, but that's the usual info from AdWords.