Checkout Success extension allows you to show more details on checkout success page. You can enable to show order details which include list of ordered products, billing and shipping information. Also you can show two static blocks with additional information for customer.
|Enabled||Show Detailed Information|
|Show Detailed Information||Enable order information on success page.|
|Above order information||Select static block to show before order information.|
|Below order information||Select static block to show after order information.|
In our extension we use “order.success.additional.info” container to show additional information on success page.
Because of bug in Magento, this block is rendered twice.
As temporal solution you can apply the patch that fixes this issue.