I need to clear this up to, this One Piece scaling is exaggerated.
Buchi's 8.52 Feat is something that would've seriously injured Zoro had it connected. Buchi's stomping attack is a super move that he can't perform without jumping high into the air and coming back down. Even without the hypnotized amp, Zoro stated that being hit by that attack would've been bad for him.
I'm not sure of the proper translation, but an unofficial one I read stated his bones would've broken, but the official viz has him state he'll be flatten like a pancake. Either way both of them imply Buchi's attack would've done serious damage. Which means Zoro was threaten by an attack weaker than 8.52 Tons.
Zoro did overpower Hypnotized Buchi, but he overpowered his punch/claw attack. Buchi cannot produce the same force that his stomp has with a punch, it's simple physics. He's jumping into the air and using gravity and his full weight to assist in this attack. His punch clearly doesn't produce the same force.
Zoro overpowered an attack weaker than 8.52 Tons.
Buchi's dura does scale to 8.52 tons, and Zoro injured him yes. However he injured him with swords, which means he can cut Buchi without equaling his Dura. I can stab someone like Bruce Lee, but that doesn't mean I'm as strong as him. Also that has to due with Lifting Strength, not AP.
Zoro shouldn't be upscaling to this feat, since we know an attack weaker than 8.52 Tons would've done serious damage to him, and that he didn't overpower that 8.52 Tons attack. And I know Luffy isn't that much stronger than Zoro during these arcs, and Arlong only defeated a heavily injured Zoro.
Not only did he just fight one of Arlong's men, but his wound from the Mihawk hadn't healed yet either. Zoro was nowhere near top condition, so no Arlong did not casually defeat Zoro. He defeated a injured Zoro, who is weaker than his normal self, who is weaker than 8.52 Tons.
