If evaluating pilots for a training course to a new type, any sim check is better done on a sim that the candidate is not likely to be familiar with. This levels the playing field.
Of course, if the candidate claims to be an ace on the specific type, and it is a condition of employment that he/she holds that rating, then the specific sim theoretically also levels the playing field among similar qualified pilots.
It is amazing how the fakes can be sorted out in a basic sim check that requires a bit of old fashioned orientation, speed control, tracking and an approach or two on raw data.
Better than all the psycho-babble, which as has been mentioned, can be rehearsed with no real flying skills required.