Ruben/Bert, you need to upgrade out of your old 7.5 series, and in to the current 7.6 series. A lot of work has gone in to updating the descriptions and presentation of the permissions system within the past couple years (for the 7.6 series).
Bert, I see your forum is still on v7.5.8.
The reason why the permission pages have recently been seeing updates is because it can be overwhelming for people like you who have nearly a hundred individual forums with several dozen user groups to finely manage everything (these are not normal forum setups).
Ruben, those pages have been getting updated with the recent versions. Lots of layout updating, improved clarity, and documenting has been added to the 7.6 series. Work that has been seriously needed for many past versions.
