Optimizer Statistics Diff Report error

I am running 12cR4 and logged into a RAC cluster with DBA privileges. While monitoring this database, I drilled down into a SQL ID. This SQL ID has many hash values (another issue for later). I noticed a button next to the plan hast value drop down called "Optimizer Statistics Diff Report", it's not always there. Clicking on the button takes you to a screen with a list of hash values with times and check boxes. I have a couple of the items checked off. When I click on Compare, I get a message There is no data to compare. Check that your ID has enough privileges