Though there may be currently sellers at 12 on the aussie stickybomb, this sale happened almost 2 months ago. There's no way of telling whether this has always been selling for 12 keys, and if the sticky were to be updated today, you'd have to take the value at the time of the sale, which is 13.

This makes your sale ~14 keys here, not 13. Resuggest at 14 flat.