FC and Jarv, I think you are just having a misinterpretation of wording.
Na2, technically IS Platinum or at least could presumably be referred to as Platinum sinces its Sodium Chloroplatinate. Just a different version of Platinum then the older ratio method of Pd to Pt.
(In Bostick&Sullivan terms) if you are doing the traditional palladium #3 and Platinum #3 method of contrast, you shouldnt use Na2 in addition to Pd#3 and Pt#3. Na2 should be used purely with Pd#3 and no Pt#3.