@kevlin At least 2:45 must be "most likely". There is always a non-zero chance it doesn't arrive at all due to "acts of god". Then again, giving legal disclaimers by sms seems unwise...
Sometimes though, the delivery is trying to uphold their part in a contract with some consequences involved. Sometimes, if you are not there, the package will be returned. Then precise times, if correct and if they matter, seem appropriate.