Amazon is always telling me my packages will arrive between 8 and 10pm but if it ever actually gets that late, it gets moved to the next day. Do they ever actually deliver that late?
I'm guessing it depends on location activity. Around Boston, MA (U.S.). Amazon delivers 24hrs a day. I've had drops during 2 hour blocks after Midnight.
I believe it's because they hope a driver will pick it up for you. Those late night packages are delivered by contractors and they might just not pick yours on a whim probably depending on several factors.