Windows 8 Notification Center Charms bar and WinRT ToastNotificationManager clearing sync

Goal is to configure useful alerts in Windows 8 while limiting notification noise using per-app toggles and toast versus banner presentation.

The design relies on the Notification Center exposed via the Charms bar and the WinRT ToastNotificationManager API for delivery and lifetime control. Windows 8 is end-of-life and the Notification Center visual implementation differs between Windows 8 core and Windows 8.1.

There is an unresolved decision about synchronization of notification clearing between the Charms bar UI and the application internal state managed through WinRT.

Does clearing a toast in the Charms bar reliably update the app's internal notification state via WinRT? How is banner timeout versus manual dismissal reported back to the app? Is the synchronization contract documented consistently for Windows 8 and Windows 8.1?