A note on the Black Flag errors- turns out it was my LB1 that was causing this. It drives one LC, the other beacons are in the other lanes for position sensing (I have a converted 4-lane, 1 lane is for re-slots). Whenever a car went over one of the beacons, it would cause the car to send a 222 throttle value (which stuck until the next LB). This would (obviously) go over the limit and cause a Flag. I re-flashed the LB and switched beacons around, no more errors. I used the car data feature in the RMS to see this occurring.