He (rightfully) beat Nam on PCS in the FS, but Nam's FS total was higher.
Jason won silver partly because he was six points ahead in the SP.
I just re-watched Jason's program. I was too nervous to really watch it while it was happening. It was still a beautiful performance that he never gave up on. He deserved the high PCS for his amazing spins, footwork, choreography and musicality. Skate America was not his best performance last year and we all know what happened after that.