smol het

Re-re-suggesting because I forgot to put the high end at 19... sigh

Sale 1:

https://backpack.tf/profiles/76561198096210931?time=1447228800&compare=1447142400

Sold for TaW DeGroot Experience

x = 21.5 * 0.9 (DeGroot was offered)

x = 19.35, rounding down to 19.

Sale 2:

https://backpack.tf/profiles/76561198096210931?time=1447401600&compare=1447315200

Sold for Aces High Armored Authority + 8 ref

Mini for Armored Authority:

https://backpack.tf/profiles/76561198096210931?time=1447488000&compare=1447401600

Sold alongside 1 key for a Steaming Caribbean Conqueror.

Conquerer Micro:

https://backpack.tf/profiles/76561198096210931?time=1447574400&compare=1447488000

Sold alongside 9.33 ref for a Duped C. Bubbles Tough Guy's Toque

Toque Nano:

https://backpack.tf/profiles/76561198096210931?time=1447660800&compare=1447920000

Sold for 21 keys

Back to Conquerer:

x + 0.55 (keys were 17 ref back then) = 21 (Conqueror was offered)

x = 20.45

Back to Authority:

x + 1 = 20.45*.9 (Mistake on my part, the Authority was actually offered.)

x = 19.45

Back to Little Buddy (finally!):

x = (19.45 + 0.49 (keys were 16.33 back then)) * 0.9

x = 19.94 * 0.9 (authority was offered)

x = 17.95. Rounding up to 18.

Sale 3:

http://backpack.tf/profiles/76561198061376237?time=1448265600&compare=1448352000

Unsure what this was bought for? Not using.

Sale 4:

http://backpack.tf/profiles/76561198063499548?time=1448611200&compare=1448524800

Appears to have sold for 18 keys.

Sale 5:

http://backpack.tf/profiles/76561198049166729?time=1448697600&compare=1449129600

Also appears to have sold for 18 keys.

Conclusion: 3 sales at 18, 1 at 19. I am pleasantly surprised at how neat this is. Feel free to tell me if I did anything wrong in the comments!