A lot of people confuse Order form impressions, order form submits, and sales!
OFI simply means they went from the vendors pitch page to the clickbank order page (where they would enter their payment details)
OFS are when they ACTUALLY enter that information and click the "order Now" button. This is NOT always a sale. There credit card could be invalid, they could have not entered all the information, or CB could be having processing "issues".