I received a package today; UPS delivered it by 5pm. I received an email last night that the package is coming, and I received an email five minutes after delivery notifying me that the delivery has occurred. That's how it should be done.
A week ago I received a package from Amazon, via USPS. The mail carrier dropped the package near the mailbox and didn't even bother to push the intercom button. I noticed the package later this day, because per USPS the delivery was scheduled for the NEXT day and I wasn't looking for it. If USPS is a day off in their very careful calculations of local delivery, talking to them about timestamps is entirely pointless.