I would guess that there are specific people at USCIS assigned to specific categories for most of the time. If there is a surge of N-400 than a slowdown in N-400 processing should be expected. They probably can assign naturalization cases to people who do e.g. I-485, but I am not sure if this is practiced. The surge in N-400 has happened due to elections + ELIS troubles + January executive order scare (remember than green card holders were initially supposed to be banned too). There is a lot of GC holders who never attempted to naturalize and if all of them tried to apply right now then USCIS would be backlogged for years.
My husbands application was received March 23. Had fingerprints done April 10 and nothing since then, online status still says fingerprint appointment has been scheduled. We are going through Fort Smith, Arkansas.
Mm1 got a reaction from casualuser in N-400 - March 2017 Filers
Mm1 got a reaction from OmaNE2 in N-400 - March 2017 Filers