[snip]

Oh, you mean that if both legs are fully loaded, there's no current being
drawn at all?

Sorry, but you don't understand. The current in the neutral is in fact zero,
if both legs are loaded exactly equally -- and if all the loads supplied are
120V loads, then it is in fact drawing 400A @ 120V.

That current is 200A. That 400A is obviously not in the neutral. WHERE
is it?