Whether or not ND deserves to be #3 or #4 , it's hard to jump another team that is also winning. Yes, PSU struggled against Minnesota, but they still won on the road. Add in the fact that the 12 team playoff is skewed to prop up the two super conferences, I can't see the playoff committee having ND jump PSU..
Claim all you want that ND beat a #19 Army, but Army did not deserve that ranking just like IU did not deserve their high ranking. The committee clearly doesn't weigh schedule strength in their rankings even though they are supposed to.