Hmmm - I checked some JP sites and PROBABLY (but you have to check it) these new fighting styles give 2-3 more mobs to kill. Maybe that's the difference.
On the side note - I also thought that "Soothing healer" would give new spells that are available for WHM but are not used by NPC (like Erase, Banish I & II, Holy, Regen I & II, Curaga I & II & III).
BTW - my NPC is almost lv. 56. Does your NPC (>=57) use Shell III?