Note: I am actively trying to buy this part, shouldn't affect the nature of the proof though. The price appears to be crashing hard

SOLD

http://tf2tp.com/trade.php?trade=9276148 (1.66 - outlier)

http://www.tf2outpost.com/trade/9531803 (1.33 - outlier)

http://www.tf2outpost.com/trade/9523047 (1.00)

http://tf2tp.com/trade.php?trade=9272747 (0.33 - outlier)

UNSOLD:

http://backpack.tf/classifieds/search/tanks (1.00 and upwards)

http://tf2tp.com/trade.php?trade=9277165 (1.00 - still in bp)

http://www.tf2outpost.com/trade/9543147 (1.00, no offers)

http://www.tf2outpost.com/trade/9539758 (1.00, no offers)

http://www.tf2outpost.com/trade/9540106 (1.00, no offers)

http://www.tf2outpost.com/trade/9535001 (1.22, no offers)

http://www.tf2outpost.com/trade/9527893 (1.22, no offers)

http://www.tf2outpost.com/trade/9525781 (1.33, no offers)

http://www.tf2outpost.com/trade/9526185 (1.33, no offers)

http://www.tf2outpost.com/trade/9538568 (1.33, no offers)

http://www.tf2outpost.com/trade/9301143 (1.33, no offers)

http://www.tf2outpost.com/trade/9495621 (1.33, no offers)

BUYERS

http://www.tf2outpost.com/trade/9521655 (1.00 - at least one add)

http://www.tf2outpost.com/trade/9395449 (turned down 1 ref twice)

http://www.tf2outpost.com/trade/9497533 (0.66 - at least 2 adds)

http://www.tf2outpost.com/trade/9478860 (0.66 - at least one add)

http://www.tf2outpost.com/trade/9473650 (0.33 - bought one (My trade))

So clearly parts at 1.33 aren't selling and the high end isn't valid, a few outliers doesn't disguise the number of unsold parts at 1 ref (without a single offer)

1 refined seems to be the convergent price point between buying and selling prices (where most trades happen). There are a few outliers above and below the suggested price as can be expected.

Please point out any flaws in my reasoning!

Edit: apparently I can downvote my own suggestion, who knew?