I know that it's not really safe to throw out randomly unless its an EX maybe but I just took it for reference. It sometimes is good if you've done the EX upper loop for some time cause it will reset the combo (thus the damage scaling) and people that are being comboed by the EX upper loop usually go into crouch block mode because 1) If one of the EX uppers would whiff, you wouldnt be hit 2) People are too afraid of getting baited into throwing out a random reversal SRK unless theyre total scrubs.
Also, if you call THAT link hard, I feel sorry for you

. Dash Overhead gives +10 on hit, cr.LK hits on the 5th frame. Anyone can link this after a few tries.
And how can you NOT confirm the headbutt after the overhead? It's not like you recover instantly from it. I feel like theres enough time to confirm the hit (besides, you can just press LK after the overhead since it will only connect if you've hit with the overhead anyway, else you're at a huge frame advantage and you will get punished anyway q: )
I also know that you dont have to be in the corner to juggle with the combo mentioned above (no matter which one, Jab, Strong or Fierce. I just mentioned that as well cause you stated the KPKK Ultra doesnt juggle properly in the corner).