Hi Roger,
Thanks so much for reaching out!
With the way that you have the tickets set up, there isn’t really a way to separate which tickets will use a coupon code and which won’t. However, one thing you can do is to set up the “free” tickets with an RSVP or set them up as separate tickets with the coupon code, so that there will be a difference between the two.
Also, if you go to WooCommerce < Reports, you can see more detailed information about your sales, including coupon-related information.
Let me know if you need any further clarification!
Thanks,
Jaime