I think that is a technique which uses shinsoo inside stuff to wreck it. That's a fundamentally different technique and topic from internal quality shinsoo control.I don't remember if you guys remember. During the floor 20 test one of the test was a game to test everyones internal shinsu. Baam used piercing butterfly so I'm guessing and type of punch could be called internal shinsu. I think the meaning of internal shinsu is much bigger than body hardening. Baam can easily take powerful shinsu attacks but physical attacks are his weakness. I could say the reason Baam can't tank attacks is because his body hardning is piss poor but his speed and power are crazy high. Baam does have amazing defense from lack of his body as we saw from the Data Zahard fight.
My point being internalizing shinsu is different for everyone and it's not just body hardning but all around. One could still have a powerful punch but a weaker body.
Bam's shinsoo reinforcement is probably good, but not as good as for someone who has that as shinsoo attributes (and ha or miseng). In more recent fights he has even begun relying more on his blue oar for movement, probably because he wouldn't be able to keep up without it. This way he relies on his shinsoo control for movement rather than on his weak body and probably just good reinforcement.

Kinda funny that it leaves open the possibility that Bam can go back to being a normal dude when it’s all done. 