If Knox was briefed by her lawyer, Anne Bremner, then she may want to check the facts with another lawyer. It appears that Bremner is glazing over the little words, like "Requested Party."
"Extradition shall not be granted when the person sought has been convicted, acquitted or pardoned, or has served the sentence imposed, by the Requested Party [this means the US] for the same acts for which for which extradition is sought."
Knox has not been convicted, acquitted or pardoned, or served a sentence in the US for the murder of Meredith. She has served 4 years in jail in Italy, three of which were for the false allegations against the bar owner. During the appeal stage of the trial, she was released. That appeal process was reviewed and annulled, so the appeal process will be repeated. It could still go either way, but the ruling that she lied to avoid the consequences for the murder is part of the appeal. That is, it is confirmed that she lied because of the murder, so it's difficult to argue that she didn't commit the murder ... it becomes illogical to have one verdict without the other.
Perhaps Knox is thinking that because an US fighter pilot, a colonel and 22 CIA people were not extradited from the US to Italy, that means that she too won't be extradited. This would also be an error, as there is an exemption clause in the treaty for military personnel. Knox is not military.
I find it very interesting that Knox and friends are continuing to explore tactics for avoiding the consequences of a murder conviction.