Yes its quite a dramatic price leap, but I has proof.

Four trades on outpost:

http://www.tf2outpost.com/trade/10857696

-rejected offer of white bill's + 9 pure

-rejected offers below that

http://www.tf2outpost.com/trade/9860941

-not looking to sell for pure but has rejected an offer of 17-18 keys

-other offers are either lower or for the set

http://www.tf2outpost.com/trade/11761330

-offer of clean spine-chilling skull 2011 (24-30 keys) + 2 keys, although I think the person has it either confused with the regular spine-chilling skull or doesn't know his/her prices. The skull isn't in their bp anyways.

http://www.tf2outpost.com/trade/11081952

-offer of white bill's + 8 pure (same guy as first trade) which is being considered

-offer of voodoo juju (not sure if clean or not) but isn't in person's bp now

-other offers below those