Board Thread:Questions and Answers/@comment-31999758-20181003191945/@comment-26366865-20181010205608

https://kancolle.wikia.com/wiki/User_blog:Kappakaze/Something_on_Overkill_Protection

In short, due to the way overkill protection and rounding work in the game, ships with an HP value multiple of 4 are considerably more likely to be shot straight to taiha. This is particularly important for DDs, who tend to get overkilled pretty much all the time.