I got it back :D

Sale #1:

Bought mine for a Searing Plasma Pencil Pusher and the seller added 16 keys:

http://m.imgur.com/lCVAfVV

Proof the effect of the Noir: http://m.imgur.com/YK8AR08

Proof of the effect of the Pencil: http://m.imgur.com/UNFuMQw

Total: 80*0.9 = 72

72 - 16 = 56

Buyout of the Noir was 52 keys:

http://www.tf2outpost.com/trade/26991667

Its value caps at 52 keys due to the buyout.

Sale #2:

Sold for 60 keys:

http://www.tf2outpost.com/trade/26484826

Proof that it sold for keys:

http://m.imgur.com/VpdgFHN

History of first key: http://m.imgur.com/lsSYCj2

History of the last key: http://m.imgur.com/nI13EJW

Total: 60 keys

Sale #3:

Offered on and sold for a Flaming Lantern Cosa Nostra Cap and 10 keys:

http://www.tf2outpost.com/trade/26965890

Proof of the trade:

http://m.imgur.com/krxwpt3

Proof of the effect of the Cosa:

http://m.imgur.com/Bs8tWcV

There's currently a suggestion for the Cosa which is outdated:

http://backpack.tf/vote/id/55f0b5edba8d8884238b4602

Total: 45.5 - 10 = 35.5

This seems like an outlier due to it being way lower than sale #1 and #2 and it is also being used in the Cosa suggestion.

Please tell me if I did anything wrong.