i was told that all SEN/HON get auto checked in 2 hours before the flight. full or not. but you should regardless be able to get your BP out of the machine and not have to go to the counter.
Would also say it has no influence on op-ups. Received them as early as the evening before as late as at the gate when they put the boarding pass into the reader. so am tempted to say they come independent from time of check in.