I'm afraid they are used (see ufopaedia). Also, misc1 and misc2 are not ranks, they spawn all sorts of ranks (hence "misc"
as Volutar says this field is not a strict rank, it's an abstract rank, which can be used by a lot of ranks in a certain priority. The rank displayed in mapview is just the one with the highest priority on that list. Aliens have 7 ranks, with 2 possible units for the terrorist rank.
