6 Mg is technically correct and it has the advantage that 1 tonne (or metric ton) = 1 Mg exactly, so it's just a simple substitution of words without changing numbers.
At that point in the article, I wanted to ease the reader into the metric system and not introduce too many new concepts all at once.
At that point in the article, I wanted to ease the reader into the metric system and not introduce too many new concepts all at once.