SCS vs 32 - Insane settings + difficulty slider

I was planning on doing an scs run on insane difficulty (monsters do double damage). With the new scs, it says strongly not recommended to uncheck the box which adds the extra damage stuff even if you are on insane. Why is this? Is it because insane settings already edit enemies?

I want my game to be kinda similar to old scs + insane settings in game, but want to follow suggested scs settings.