Hitfix's Alan Sepinwall has a long interview with Parks and Recreation co-creator/showrunner Mike Schur today, in which he reveals they made the first of tonight's two new episodes a possible series finale because NBC had only ordered a 13-episode season originally (didn't they say they'd ordered 22?). The network ordered nine more episodes for a full 22 shortly after the episode was filmed, but the writers made it a special episode with a sense of closure just in case. Here's Schur explaining the situation:
"The way we operate every year is we that don't know what our future is. So we try to tell the juiciest, most interesting stories we can tell. And at the end of the year, we write a series finale. Something that, if this is it, we go out the way we want to go out. And we try not to close it off so completely that if the show comes back for another year, that we have nowhere to go …
And so we had this kind of Spidey sense that if we wanted to make a hundred percent sure that we would not be caught unaware, that we should build to something around episode 13. And we did that. We got our back nine, so we’re going to go all the way to 22. So there is a kind of little thing that happens in episode 13 where the idea was, 'We’re going to assume we have a full season, but just in case to be extra sure, we’re going to build to something in 13, and we’re going to stick to it.' That even if we got our back 9 order, which we did, we wouldn't deviate from the plan. We would execute that plan and then just go past it."