Once more.

Sale 1: Seems to be involved in a bulk deal for Purple Energy Brown Bomber

http://backpack.tf/profiles/76561198125745763/#!/compare/1455955200/1456041600

Should be used to update the bomber.

Sale 2: Sold for 11 keys

http://backpack.tf/profiles/76561198125745763/#!/compare/1456387200/1456473600

Sale 3: Sold for Strange Festive Sniper Rifle[10 keys] +Taunt: Mannrobics[2 keys]

http://backpack.tf/profiles/76561197992703391/#!/compare/1457938800/1458025200

10+2=12 keys

Sale 4: Sold for 12 keys

http://backpack.tf/profiles/76561198068219260/#!/compare/1455523200/1455609600

Buyer at 11 keys

http://www.tf2outpost.com/trade/28024880

So I have sales at 11, 12 and 12. 11 seems to be an outlier due to the buyer at 11, making this 12 keys flat.