You are just going to have to trust me. I have done WU on 5 systems today alone. Task Manager never showed more than 25 to 50% in any case. If you are at 98%, there is a lot more going on in your computer than WU.
I have seen CPU go to 100% in instances where someone started WU, "stopped it", then restarted it.
I do believe your system CPU is clearly at 98%, but I am confident there is a lot more than WU being processed.