The Exterior Backup controls where the Blade Plunges into the Matboard (not the Fallout) on the Exterior Cuts of objects.
The Exterior Cut is where the Blade Plunges/Retracts from the Matboard (not the Fallout).
If the Exterior Backup is leaving a Hook in the corner, Increase the Exterior Backup.
If the Exterior Backup is cut Too Long, Decrease the Exterior Backup.
If the Exterior Backup is cut Too Short, Increase the Exterior Backup.