Great question. From what I can tell, the issue is that in the played games, assisted tackles are a little too rare, while in simmed games, they're entirely too common. And they count as "full" tackles if you sort them in the stats screen... Except they're made up of both full and assisted tackles. It's kind of weird. And the CPU in the background seems to think assisted tackles < full tackles. Ideally, assisted tackles would be eliminated for every player, to compare them equally.
I don't use the editor, I don't want to risk my file and it just adds another level of depth to what is already a time consuming (but really fun without the editor) process for me. Somebody else may be able to answer whether this is possible.