Does UPS routinely lie about delivery status?

I'm an Amazon Prime customer. Since signing up for Prime, I have found that the package delivery status has become noticeably less reliable. There were always odd seeming revisions to package status when I was using best-effort delivery, but now that I am supposed to get two-day delivery, I find that the status is misreported, indicating my package was delivered when it was not.

Have you noticed a similar drop in quality of status information from UPS and/or Amazon?