Not sure Von will be in Stage 3.
The 6 game suspension was down from a year long suspension that the NFL wanted to hand out.
Here's the gist of it -
Von spilled his sample (getting him to stage 2), was immediately asked to provide a new one and that one was diluted (getting him to stage 3).
The spilled sample wasn't proven to be positive, and so the next sample was diluted (but not positive for banned substances) because Miller had to drink loads of water.
So beyond the final result of him getting a "lesser" suspension from 1 year to 6 games it's not clear that he IS in stage 3 and I doubt we'll know for sure as it's supposed to be confidential.