So if it costs energy to unbind weapons and armor, I don't see why accessories aren't subject to the same rule. It's just silly, destroying an accessory just because you found a different armor you'd think it'd look better on. I'm sure this has been mentioned before, but the more threads about it that appear, the more likely developers will take it into consideration.

As far as cost goes, it should be one simple flat rate, since none of the accessories have levels. 400 - 500 EC sounds like a good figure to me.