I have this feeling that it's a confidence thing. Past tense sounds so definite - 'this happened, definitely', recounting something that has already occured, and I'm still feeling my way with where this story is going, so the present tense is more comfortable because in a way I'm going along with the characters, and whatever's to come, I don't really have any more idea on the specifics than the characters do. I mean, I've got it plotted out, but ... yeah.

Incoherency ftw.