Board Thread:Wiki Discussions/@comment-3238846-20140422105553/@comment-17623-20140424110024

Who knows. Perhaps Kishimoto was lazy. Perhaps Yamato used the example "I'm mixing them in both arms" to explain it easily to Naruto (whom it is listed even here, as needed an oversimplified explanation to grasp certain things).

I'm pretty sure we've seen Wood Release users do stupid things with only one hand. And even then, that ignores the fact that (yes in their explanation) that there isn't such a thing the advanced natures (in their explanation, wood) at all, and that it is formed directly because of the mixing of two elements. So even if the chakra was "handed off" it is still the mixture of the other two, for the simple reason that it has to be to even exist.