I think you misunderstood - AR7s are designed to be mounted 2.5cm back. If you mount them centre it does interfere with turn radius, flex etc. The Moments are designed to be mounted at centre. If you mount them anywhere else then you are also messing with turn radius and flex.
If you want solely a park ski, get symmetrical. If you want a ski to carve round the mountain on and do park, get asymmetrical.
Why armada dont offer a symmetrical ski i dont understand. If the AR7 was i would buy it in an instant.