What should the "Ship From" address be when dropping off a prepaid package at a USPS Post Office? Can it be set to the address of the post office? The closest post office to me has a different zip code than my address because I live near the zip code boundary. The clerks are claiming they only accept prepaid packages with the same matching zip code. eBay allows you to have different "Ship From" and "Return" addresses, but I'm wondering if anyone can confirm whether it's permitted to use a post office's address as the "Ship From" address.