Sion drops 2 Dark Harvest stacks?

I feel like this is overpowered. I just had a game where I killed Sion like 6 times and got 12 stacks from him alone. On old dark harvest that was fine but on new dark harvest I think it should be changed. I know it kinda makes sense thematically for him to do so but...if there is a Sion you can just camp him and get soul after soul which over the course of the game would get you to some ridiculous stacks.