Quineloe
Ahn'Qiraj Raider
Even without any crits the sunder method actually defeats the mob. The HS method loses the fight. And yeah, overpower crits. because you're using HS, you have less chances of triggering overpower. So of course the SA method gets more crits.
The reason your mobs die in 3 hits is because you're fighting mobs bordering on grey with a weapon that is essentially epic at your level. Your WW Axe is ilevel 40. On BoE the required level for ilevel 40 stuff is level 35. You'll not be able to twink that kind of powerlevel with a blue weapon again.Now make one on a nonelite NPC that dies in 3-4 hits