If required, it is possible to allow conversions to be tracked via the referral URL, even if the affiliates coupon isn’t used on the order.
This means if someone visits your site via a referral URL and places an order without using the coupon, or uses a different coupon for a better discount, you can still track the referrals for that affiliate, and provide the appropriate commission.
To enable this feature, simply go to the “Referral URLs” settings tab, and enable the option under “URL Conversion Tracking”.