In the compare you provided for sale 1 ( https://backpack.tf/profiles/76561198125791160#!/compare/1528329600/1528416000 ) there is clearly 1 key along with the cap that matches histories.

Lucky for you the 12 key sale as mini for your fez was to a buy order and I would exclude it, making the fez mini 14 keys. 14 - 1 is 13 keys again and due to both of your mistakes cancelling each other out the suggested price ends up being correct.

Not awarding points for this however.