Creds to Jarool for 100% proof here

Copy-pasted:

Sale 1:

Sold for Miami Nights Bicorne (Suggestion at 19.5)

http://www.tf2outpost.com/trade/29399577 - B/O of 21

Seller: https://backpack.tf/profiles/76561198106495563#!/compare/1508025600/1508112000

Buyer: https://backpack.tf/profiles/76561198219836673#!/compare/1508025600/1508112000

X = 20

Sale 2:

Sold for Logo Defiant Spartan (Suggestion at 18.5)

No outpost

Seller: https://backpack.tf/profiles/76561198158905381#!/compare/1510790400/1510876800

Buyer: https://backpack.tf/profiles/76561198260851164#!/compare/1510790400/1510876800

X = 19

Sale 3:

Sold for Terror-Watt Hustler’s Hallmark (Suggestion at 15.5) + ~3.5 keys in items (after ~3 day trade hold)

http://www.tf2outpost.com/trade/29406273 - B/O of 22

Seller: https://backpack.tf/profiles/76561198219681600#!/compare/1510012800/1510272000

Buyer: https://backpack.tf/profiles/76561198150531550#!/compare/1509926400/1510272000

X = 19

Sale 4:

Sold for Max’s Head (18 at the time)

http://www.tf2outpost.com/trade/29385789 - B/O of 20

Seller: https://backpack.tf/profiles/76561198112564673#!/compare/1507075200/1507334400

Buyer: https://backpack.tf/profiles/76561198108807321#!/compare/1507248000/1507334400

X = 18

Sale 5:

Sold for 15 keys

Seller: https://backpack.tf/profiles/76561198091203041#!/compare/1506729600/1506816000

Buyer: https://backpack.tf/profiles/76561198112564673#!/compare/1506643200/1506816000

X = 15

Sale 6:

Quicksold for 15 keys + cheap item

Seller: https://backpack.tf/profiles/76561198324692104#!/compare/1510617600/1510790400

Buyer: https://backpack.tf/profiles/76561198158905381#!/compare/1510704000/1510790400

X = 15

Sale 7:

Bulk for Kill-a-Watt HKC

Seller: https://backpack.tf/profiles/76561198108807321#!/compare/1507852800/1508112000

Buyer: https://backpack.tf/profiles/76561198219681600#!/compare/1508025600/1508112000

Miami Bicorne:

https://backpack.tf/suggestion/5a1e6a7944325a5c7b5fcf1b

Terror-Watt Hallmark:

https://backpack.tf/suggestion/5a1e6f6acf6c755f68410b2b

Logo Spartan:

https://backpack.tf/suggestion/5a1e786844325a5ccf296446

Sales at:

15 (2x)

18

19 (2x)

20

No current sellers.

Buyers at 15. Excluding 15.

Going with 18-20.