If you don't see your sponsored ad cost under the "i" where the fees are broken down, please make sure the Sponsored Ad setting is checked:
1. On the top right of the Merchant Dashboard screen you should see the Merchant Name Options drop down menu. Click that and select Settings link.
2. Once the settings open, check the option that says "Include Sponsored Ads In ROI, Margin & Payout Reports".
3. Click Save
Sponsored Ad Cost are always 1 day behind as Amazon only provides this data once per day for the previous day.