The total media cost is the combined price of buying impressions (media cost), combined with the fees for using any third-party audience segment data (data fees) and any partner costs, such as the fees for using Display & Video 360, a third-party ad server, or a third-party ad serving verification service.
You can include the Display & Video 360 fee (platform fee) in the total media cost by checking "Automatically put platform fee as Media Fee 1" in your partner costs. This option overrides the "Media Fee 1" field with the platform fee for all your line items.
If you don't include the Display & Video 360 platform fee in total media cost, the Display & Video 360 fee will only be included in the billable cost.