Allegedly those F100s are coming off the VARA RPT side of things (think BME, KTA, etc). Apparently that flying to be picked up by PER 737 (maybe A320 too?). Although what that does to costs when you have a 100 seat jet replaced by a 170 seat jet - who knows? But I suppose that’s similar to some of the routes that were purely ejet back in the days.
Its a necessary move, F100s close to 30 years old will no longer be acceptable to VARA's resource clients travelling to BME/KTA etc.