Sniper's Mark: number of splits and curse effectiveness

Cheers,
as I couldn't find a Sniper's Mark thread in the gem section, I try it here.

Does curse effectiveness has an influence on the numnber of splits? PoB says I have a Curse Effect Mod of 2, and I thought that this would increase the number of splits, but ingame-tooltip still says "split towards 2 additional targets".

Is it just a tooltip bug, or does curse effectiveness just have no influence on the numnber of splits?

Thanks