Solved

Research bug

The weakness of your chief designer is downforce. In that case you gain only half of the normal points.

 My answer looks a bit weird now that the original post got removed :D
Message to mods/devs: it now looks as if I'm reporting about a research bug, but I was actually answering to the original poster why he gains less points when researching downforce compared to other attributes. 
I think this topic can be closed now ;)