I think you enjoy arguing. But anyway lets go...
Ok lets take 1993 For one six race period Hill scored 41 points to Prosts 18. So thats Prost disproved.
I havent looked at the stats, but from what I recall, Prost have serious car problems during this period. The fact that he was outscored by Hill was not based purely on performance. My arguement was also be that Prost was in his final year of F1 and was no longer prepared to take unnecessary chances.
Mansell, well lets forget about 1994 and 95 shall we I'm pretty sure Mansell was beaten consistently in 1990 by Prost.
Right. Mansell beaten in a Ferrari where MAJOR shenanigans were taking place. There were points during that season where Mansell would go fast in qualifying. Prost would then (overnight) have his and Mansell's cars swapped. If Mansell went slower, then fine. If Mansell went faster still, (overnight), Mansell would have his car swapped over again. This had major effects on Mansell's performance, while he was at Ferrari with Prost.
Last 6 races of 1989 Berger 22 points to mansells 4.
First 6 races of 1987 Mansell 23 points Piquet 24 or of if you want to go to first 9 races Mansell 33 points Piquet 50 points.
Onto 1986 last 7 races of 1986, Piquet 43 points mansell 26 points.
The mid-80s were when Mansell was improving. He never arrived in a blaze of glory like Senna or Hamilton. He improved gradually. But when he reached the top, he was awesome and could then be classed as a top-line driver.
Piquet in his time, for those who don't know, would be the equivalent of Alonso or Hamilton. Triple World Champion, which neither Alonso or Hamilton are currently.
I think thats going far enough to prove mansell didn't consistenly beat his team mate, by using your reckoning and '6 race theory' you can use any stats you like to make someone look bad.
The above stats prove nothing because it doesn't take into account external factors affecting reliabilty, accidents or even the quality of your team mate.
But hey you wanted Facts.
Now if you look at Button. This is HIS year. This is his best year and this year he is now losing ground to his team-mate. Furthermore, he hasnt lost ground due to unreliability or similar. He has had 1 DNF (which is pretty damn good). The simple thing is that he is losing ground in qualifying, which is affecting his race performance.
EDIT: I shall pull some facts regarding Berger VS Mansell, as by then, Mansell should've been able to outscore Berger, but I'm a little busy right now.