Probably because even a Minion Necro cleared T98 already - that is broken OP and has to be nerfed to maximum clear T80 next season! 
Meanwhile I would not wonder if in S7 a nerfed Quill Volley SB would clear T130-140 while new METAS do T150 again. 
Raheir is also going to get nerfed to 45% dmg reduction - my guts say.