Tiger, they confused you, didn't they?
SAS, short term stabilization,
YOU fly the helicopter with or without force trim (a lot more fun).
ATT, long term stabilization and requirement for coupled operations, the helipilot computers fly the helicopter, the force trim HAS to be ON to couple the Flight Director.
ATT is the required mode for IFR flying.
Just like the 412, provided you are talking about a different helicopter, like the AW-139.
