I think you're in luck!
Milecalc.com and Flying Fish both show this itinerary as 10,644 MQMs.
http://milecalc.com/schmutzig/?paths...DX-NRT-PDX-SEA
I don't think you're allowing for 500 mile minimum on the short hops. Are some of those Alaska Air flights? That might make a difference.
Platinum status has no bearing on MQMs, unfortunately!