Yes.

When a user views the drill-down report for a dashboard component, running user's access permissions determine what data is displayed on the drill down report. Hence it is possible that data in the drill down report does not MATCH the cumulative dashboard data.

Remember report runs based on current or logged in user and DISPLAY REAL TIME data but dashboard store the INFORMATION from reports when you refresh dashboard. In order to see real time data on dashboard, refresh the dashboard.

Also dashboard can run based on logged in user or specified user but reports always runs based on logged in user.

Yes.

When a user views the drill-down report for a dashboard component, running user's access permissions determine what data is displayed on the drill down report. Hence it is possible that data in the drill down report does not match the cumulative dashboard data.

Remember report runs based on current or logged in user and display real time data but dashboard store the information from reports when you refresh dashboard. In order to see real time data on dashboard, refresh the dashboard.

Also dashboard can run based on logged in user or specified user but reports always runs based on logged in user.