i reached a PR where my challenge bonus is not at 100% when i stick to my high-pr opponents.
I do get 100% choosing those high score but low pr opponents, but my stats show me lower xp/cb$ rewards for those:
From top to Lord Bob are low pr but high score, showing the 100% challenge bonus, the lower ones are higher pr with not 100% but still higher average XP per minion. (The number on the left is the number of fights that were averaged, the +- at the end is the statistic confidence interval).

Somewhere in the forums or help is said "everyone in the 6BA range does not receive negative challenge bonus".
How is this to understand? Does it mean i won't get negative challenge bonus only (like never -20%), but that it's simply not possible to get 100% anymore?
Is there maybe some rule that only applies to the top 10 players in score/pr/mpr or whatever?
Does the displayed challenge bonus change, or is the reduced penalty only applied but not shown?