When you don't do any input but your guy still manages to break free, that could be Elusiveness or Trucking. Both of those ratings are used for CPU ball carries, and when you take on a tackle without doing input I believe you get treated like a CPU ball carrier. One thing I'm noticing in your posts is that you aren't mentioning Elusiveness at all, while I personally think Elusiveness is the primary rating for "slipping" tackles. Not running over a guy, but the animation you see where the defender gets one hand on your player and slips off ... that's Elusiveness. That's why I look at the Elusiveness of my guys before I pick my PR/KR, and it's effective in my eyes.

It's also possible that I received incorrect information and BTK is actually used in tackling calculations after all. We're basing this entire conversation on the foundation that I'm actually right

The CPU controlled players are getting the same type of dice rolls that a human-controlled player does. CPU controlled players try jukes, trucks, spins, whatever, just the same as you and I -- when it's human controlled it just waits for human input, the calculations are still likely done with the same variables and ratings. I don't believe NPC versus PC has largely anything to do with it.