Was this a regularly scheduled hourly caf or a manual caf? Regularly scheduled cafs that drop each hour pull stuff that is 70% empty or more. Manual cafs pull stuff that is only 30% empty. So there is a big difference between the two in the amount of stuff that comes out.
If that was an automatically dropped hourly caf, I haven't heard of those at 6pm. Cafs normally stop at 5, although I know that super high volume stores also have 7pm cafs.