If you watch the show (and I've watched it a lot) you can tell that Aaron Sorkin wasn't writing to a detailed plan. I think a lot of his ongoing storylines grew organically (and were often turned in very late, which ultimately led to him being sacked from the show), which meant he sometimes repeated, or retconned, beats, or made other mistakes.
Hartsfield's Landing was probably named after Hart's Location, another New Hampshire town that has often votes at midnight. I recall reading a story that, because of the weather, of the three towns that usually do vote at midnight only Dixville did so this year.
edit: Hrrm. Turns out that's what the linked CNN story actually says. Serves me right for not RTFA.