With autotracking, the guns aim for the ITTS reticle on your behalf. But the correction angle is limited, so you still have to try and aim for the reticle yourself. The shots don't curve, but by aiming for the reticle, they have a greater chance of arriving at a spot at the same time as the boggie passes through that point. But ITTS is useless on a boggie that comes at you drawing circles with its nose, notoriously the way kilrathi ships fly. With autotracking on, your shots spread out all over the place, so it's best to turn autotracking off untill the ship starts flying straight.