Yes, but that's what makes it even more cursed. SI prefixes normally bind tighter than exponents, so km² = (km)² = (1000 m) * (1000 m) = 1 million m², not 1000

Yes, but that's what makes it even more cursed. SI prefixes normally bind tighter than exponents, so km² = (km)² = (1000 m) * (1000 m) = 1 million m², not 1000 m². Meanwhile kcm applies the prefix last - so it's off by three orders of magnitude from the normal way.