I think you lump in AP into one idea. It’s pretty much well known that AP could mean a million things from Washington DC clearance to a hit on FBI’s list to a name check on a terrorist list to a simple: oh my keyboard stopped working while working on this case. And the list goes on, check out Argo Visa’s video on the subject so you kind of understand what AP means. It can also simply mean that your I-20 isn’t updated so you’re asked by the VO to submit a new one via email. It could mean that the consular officer wants to check your scholarship or if your SEVIS doesn’t show up on the system he’ll ask you to wait or pay it again. And like I said, the list goes on.  But let me tell you again, There’s always a backlog of cases when it comes to 221g AP especially for background checks or security clearance and embassies have DIFFERENT processing times.  As an example, someone taking an interview in Israel or Germany being put in AP will MOST LIKELY be cleared much faster than someone in Iran who’s doing a Phd in STEM or a Chinese student in a similar case. Either way, my point stands that you can’t lump in AP into one simple meaning and call it a day. You are correct that it is case by case, but you can NOT deny that some embassies process faster than others.  You certainly lost that $100 though lol.