Later on I found a Wingblade with the same stats but dmg +15% v. Hexed Foes. I salvaged it for the +20% and sold it for a generous sum.
I just thought I'd shine a light on this because it seems to good to be true (despite the improvements on rare drops, Chest items still have a bad reputation.)
If you decide to try this, please post your item so an informed decision can be made as to whether I got a lucky streak or there has been a genuine improvement.