I was NOT aware of the other suggestion. Nonetheless, it's only sale is wrong.

Added 3 Keys for a Steaming Samur-Eye(13 Keys with Overpay)(10 Keys total)

http://backpack.tf/profiles/76561198176960099?time=1427942667 -> http://backpack.tf/profiles/76561198176960099?time=1428735600

http://backpack.tf/profiles/76561198045618847?time=1428562800

Sold for an Orbiting Planets Detective Noir(10 Keys with Overpay)(This was the supposed 12 Key sale)

http://backpack.tf/profiles/76561198189718028?time=1433007400 -> http://backpack.tf/profiles/76561198189718028?time=1434092400

http://www.tf2outpost.com/trade/26098326

Sold for a Blizzardy Storm Brigade Helm(11 Keys with Overpay)

http://backpack.tf/profiles/76561198045618847?time=1428562800 -> http://backpack.tf/profiles/76561198045618847?time=1428649200

Sales seem to fit, 10-11 Keys should be fine.

Additional Proof/Counter-Proof/Constructive Criticism/Feedback is always appreciated.