I also have the 6MM cyclops. I am certainly no expert - but does shape have anything to do with this? When I look at genuine PAMs in the AD, the cyclops does also have distortion - but it is pushed more to the edges. If you look more directly head on with a genine - it looks very clear. On my watchmen, it is still distorted.
Moving to the 6.75, while incorrect, if less distorted, will be more believable. I doubt people could see the .75mm difference or would even be looking for that. But distortion is something that even my wife can pick up.