How Usagi gets into high school.

[WG_Writer]

If I recall correctly there is also the fact that Mihoshi's documentation of the Kagato situation was so detailed, long, and complex it took a team of scientists a long time to put it all together, and that is what delayed The emperor's visit. This could have been stratagic on behalf of Yosho to delay their arrival too. But it has been months since I watched the OVAs so I could be wrong.

[Uldihaa]

I think the report was also extremely disorganized. It's implied that she tended to go off on long, extremely detailed tangents that would themselves wander off-topic. At least that's what I remember.