Hiding / Releasing Participant Incentive Results

We have been using the 'Display period data in participant reports' checkbox to release results to incentive participants once they are ready for viewing. However, we recently noticed that participants are able to view their direct reports' results before the box is checked. It appears this only prevents participants from viewing their own data. Is this expected behavior, and if so, is there a workaround to keep all results private in participant dashboards until we want them to be viewable? In case it is relevant, the participants have the 'Incentive Compensation Participant Manager' role to allow them to view their