Well, as you can see the P6K has a 'patch range', or what we can call "reduser stops", of 15.7. Let's call it 16-. So, 16- vs 16+?
Or, we can just discount the "internet stops" that start somewhere around 14 and above and realise that the meaningful difference is absolutely zero. In that regard.
There are many other differences between the cameras though, playing to both their strengths and weaknesses respectively.