I've farmed this stuff 100s of times so imagine my surprise when this happened with 3x the required amount of ballista on a lvl 4:

battle5.evony.com/default.html?logfile/f5/ec/f5/f7/f5ecf5f7dab2886479d4ea7237dfc2a2.xml

and then this happened with 200 more than required on a lvl 7:

battle5.evony.com/default.html?logfile/b2/ef/2e/9b/b2ef2e9bc1cfd5dda0fd924eaed66ad7.xml

hero was 95atk and archery lvl 8.

Someone explain this.