After my previous suggestion for this was accepted, MarbleBlue who was involved in both of these sales, added me and told me that I got both the sales wrong in this suggestion. The first sale involved 7 more keys which were put on the market so they didn’t appear in the timestamps, and the second sale involved a CSGO knife (which also obviously wasn’t in the bp.tf timestamps either). He sent me this screenshot: http://i.imgur.com/po0JBOQ.png?1 to clarify.

Here is the re-done suggestion:

Sale 1: (outlier)

Sold for an Australium SMG plus a vintage soldier’s stash plus 7 keys

(0.7*0.9) + 9 + 7 = 16.63 rounding to 17 keys

http://i.imgur.com/po0JBOQ.png?1

http://www.tf2outpost.com/trade/24973844

Seller Before: https://backpack.tf/profiles/76561198155627042?time=1423641600

Seller After: https://backpack.tf/profiles/76561198155627042?time=1423728000

Sale 2:

Sold for an Orbiting Fire Allbrero

(45.5 + 22)*0.9 = 60.75 rounding to 61 keys

http://www.tf2outpost.com/trade/25282600

Seller Before: https://backpack.tf/profiles/76561198014463673?time=1426316400

Seller After: https://backpack.tf/profiles/76561198014463673?time=1426402800

Notes:

Mini for the Orbiting Fire Allbrero:

I checked with premium and there have been no recent sales at all. Using the current price.

Mini for the Battle-Scarred Flip Knife | Night

http://steamcommunity.com/market/listings/730/%E2%98%85%20Flip%20Knife%20%7C%20Night%20%28Battle-Scarred%29

9 sold for $52.12 on the day of the sale

(52.12/2.40) = 21.7166667 rounding to 22 keys

Conclusion:

Sales at 17 and 61 keys, calling 17 an outlier and taking the final price at 61 keys.