For the T30 tank destroyer this mod may show the crosshairs circle fully aimed and closed when it is not. Its tough to tell without seeing both reticles but I was consistently getting wild misses, even shots going outside the circle, when I was completely aimed. As I said this is with the T30 and not sure about other tanks.
For more info go the world of tanks forum - Gameplay Discussion / Battle Tactics / Unlucky RNG or fault of XVM (video)
(I posted a video on youtube but for some reason I am unable to COPY and PASTE anything in here)