The proof you provided is all people selling, which gives us no real indication of the price, and the majority of them have not had offers on their items, or are using outdated prices (the guy selling his dirty for 1.66 even stated in his trade that he made it when clean was ~5 keys). Not enough real, strong evidence to get an upvote from me.

[url]http://www.tf2outpost.com/trade/4884234[/url] key

[url]http://www.tf2outpost.com/trade/4860154[/url] 2 ref

[url]http://www.tf2outpost.com/trade/4952178[/url] 1.6 ref

[url]http://www.tf2outpost.com/trade/4902517[/url] 1.6 ref

It seems easy to get at 1.6, I don't see anyone selling for 1.3, 2 ref seems less likely, but that's why it's at the high end.

It does not matter what they sell it for, rather what sells succesfully.

The links I posted are offers or successful sales.

The excessive availability of this item for 1.66 refined means that an upper range above that price is unneeded.