Good question, Lew. One conceivable explanation might be that the triple shielding provided in the Pangea AC-14 series cords which I suspect Darkstar1 is referring to could reduce RFI pickup from nearby components, cables, or power cords. RFI that might otherwise radiate within the turntable to the tonearm leads, and result in audible effects by intermodulating with signal in the phono stage or further downstream.
Of course, if the explanation is along those lines there would be no reason to expect much if any correlation between the performance of a given power cord in one system and setup vs. in others. And not much if any correlation between performance and price, either, as well shielded power cords can be obtained at modest prices, the Pangeas being one example.
Best regards,
-- Al