Originally Posted by
Ca Putt
I'm not entirely sure, but I think Battle difficulty does not mess with armor or shield and thus does not enter into ranged casualties, I could be wrong however.
The hight would also be my guess, where we see a slightly crooked landscape without cliffs etc. the AI sees the exact hight of every ground polygon and thus automatically takes these litte bumps. The Engine takes even a slight hight difference very serious, which often results in an advantage for the AI, I presume they upped this after they saw how stupid their AI is :D