If you access the commands on the Cameo Control Panel you will see a command called "Deep Cut" after experimenting I couldn't see what difference it actually made, so I wrote to GAS and this was their reply.

QUOTE - It is a feature which enables a “tangential mode” of cutting. This is a method of cutting for some thicker material types where the blade lifts between corners and then resumes after lifting rather than making a continuous cut throughout the line set. It does not press down harder, double-cut, or otherwise provide more force for the cutting process. It simply is a method of how the Silhouette goes through the cutting process. It is not presently included in the software as we found in testing that this had caused too much confusion for users. Unfortunately, it could not be removed from the actual firmware of the cutting unit and so still appears in the menu options of the LCD screen when cutting from an SD card.