Well, to me, it just flows better when you see Yoda meditating (you know, before Bail Organa walks in the room). You don't know about what esxactly, but the camera focuses on Yoda enough to let you know he is meditating. And then it comes off as more of a shock when he explains it to Obi-Wan. We learn at that moment, just as Obi-Wan is, of the ting with Qui-Gon.

Now, imagine if Lucas had included the scene with Qui-Gon. To the viewer, Yoda's revelation to Obi-Wan would have seemed somewhat repetitive, and wouldn't have as much of a "WTF was that? Cool. Wow!" reaction, since the viewer would already know everything by seeing Qui-Gon telling all of this to Yoda.

I think it's cool that it gives us something to think about. And.. if we want a specific answer, we can choose to read the novel.