Eh idk chief. You say he couldn't have crossed over half, but why? What's the reason? A human could easily fit in there, it isn't like he's catching the punch from the side, he's facing forward, technically speaking he'd only need 25cm~ if he was right up on the other dude given average chest depth of a 1.8m male is about that so it'd be a tight squeeze but technically speaking, that's the minimum, and you have it at almost 40cm just because.
Actually calc it, you're capable. In fact, do we not see them afterward? Shouldn't it be easy to get the actual distance?
Also, him lunging doesn't mean he didn't pull back his fist either, in the scans in the feat, his arm is not in the position that he has them in in the technique you said he used. So either way he's moving his arm into position so he can even do the lunge punch to begin with, and that includes "raising" it as it's not held straight out or anything. You need to factor in where is arm was before and the position it was in, as he begins his attack as well, it's not like it just teleports into position.
This is going to drop J's speed quite a bit but there's a bit of a bonus that will mitigate it a decent bit.
If he's actually doing a lunge+punch simultaneously, that'd actually increase the top speed of the punch, ******, idk, you could use this sqrt(body lunge speed^2 + fist speed^2 + 2 * body lunge speed * body lunge speed * cos(θ)). Angle is 0 here given they're both going forward.
