My name is Ardiane, a Guru here at Shopify!
Normally, your reports in the plan that you're currently on, you would have access to the total sales only but can define it to show the total sales amount with the discounts as you can see from the screenshot below:
To get more options to customise your reports, I would recommend upgrading your plan to the Unlimited plan to enable the advanced reporting features as you can see from this doc.
Hope that helps you with your query! I'll be keeping my eye on this forum thread to see whether you need more help with this.
- Ardiane :)