The Interior Backup controls where the Blade Plunges into the Fallout (not the Matboard) on the Interior cuts of Openings.
The Interior Cut is where the Blade Plunges or Retracts from the Fallout (not the Matboard).
If the Interior Backup is cut Too Long, Decrease the Interior Backup.
The Interior Backup field is marked with a Black Arrow on the Configuration screen and the Map illustration.