Short version. On your own store the result is counted the moment the order confirmation loads, by one line on that page.
Own store versus marketplace
On your own store the result is counted the moment the order confirmation loads, by one line on that page. On a marketplace the order arrives through the marketplace's affiliate reporting, on its timeline, sometimes with a hold for returns. Shopmycode runs both in one campaign and labels each result as live or waiting so nobody is surprised.
Deal groups and reviewers
Deal-group admins and YouTube reviewers move real volume. They want the reward stated, the room left visible, and numbers they can check — all three are on their screen. Give them a fast product page and a code, then read the results by group.