I'm starting Nov 30th. I believe I will be a "PIC qualified FO", meaning I have 135 mins for freight/mail/repo/etc flights but short of ATP mins. I don't know anything about the "low time" class, maybe someone else can chime in but perhaps that means they are looking for low timers to sit right seat out in STL, though I'm not sure why they would want FOs for a specific base. Maybe it's another PIC/FO class.