Ahh I see what has caused the confusion.
I think what myself Clandestino are talking about is that the thrust axis / thrust centreline of the the ATR or DHC-8 may have be offset to counter asymmetric effects. i.e the engine is mounted slightly offset by however may degrees to the longitudinal axis of the aircraft.
But having a look through the nacelle chapter of the ATR Maintenance Manual there is no mention of an offset on one of the engines / nacelle.