Saved Search listing Discounts on Sales Orders

I am trying to create either a report or saved search based on sales orders that have discounts applied.  We use the netsuite discounting feature, not a line item to discount.

I would like a report that just lists sales orders that have a discount applied.  There is no discount amount field available when creating a report on sales orders.  I was able to create formula fields to calculate the discount but was not able to filter the report to just the discounted sales orders since it doesn't appear you filter by formula fields.

So I started over with a saved search only to find that when i pick the "Amount Discount" field, it doesn't show the discount.  When I picked the "Amount (Gross)", it still shows the net amount of the sales order.  So I can't even create formula fields in the saved search to calculate the discount.