It is hard to hit a shore battery when level bombing, but not impossible. You might take into account that you just missed?
Shore batteries are located on a raised mound of earth, with a steep incline. What this means is you have to hit it right on, otherwise the bomb blows up much further down a hill, and has no affect on the battery.
Hope this is right, thats my take on it. btw, your post was very hard to read and understand