::::::I don't think a theme song change is enough to designate a new season.  Many shows (including Monk, White Collar, and The Office) have had theme song changes midseason, and Wikipedia has never considered these to be new seasons.  White Collars return from midseason hiatus this past year was even advertised as a "season premiere", but we do not consider this to be a new season.  The fact that every reliable external source uses the 45-episode second season and that the only source used to justify the split (Nickelodeon itself) is sending mixed reports out should be enough to go back to the 45-episode plan.