Back when I did the preload and air exception work, I worked a lot of Saturdays and the only time I got 40 hours was during peak or when there was a streak of bad weather and I ran late air.
There was also the 'flavor of the week' times when OT was discouraged. When it was not discouraged, we could help guys run air so they did not have to backtrack too many stops. Sometimes, the bosses would not let us take a board along. No board, no delivering.
Right now, my building is really stressing NO PT OT. We had 1 day of late air, so an exception person working today would be at 30ish hours for the week.