OK, after being in the habit of crunching tons of stuff for ess, I messed up.
I was in autopilot mode, and turned a +2 Addy Tower Superior Dev 2 Spell Resistance 17 with large augment slot into 4 arcane essences. I meant to make it craftable.
Ouch.
It would be great if the buy back feature of the vendor in the crafting hall, kept track of what u crunched. Then charged essences to give u the item back.
Lets take that shield, it had 2 arcane and 4 arcane (I forget type). Suppose the cost was the sum of any essences you got from crunching. I think that would make it something that wouldnt be abused. I dont see the advantage in people trying to abuse it for other components.