Do I Need to Wait in a Line at Post Office for International Packages?

     Today, my husband and I went to our local Post Office to send a package to Japan. While we were waiting in a line, a USPS staff told us that we didn't have to wait if we had paid for it on online in advance. I told her that we thought we needed to wait for it because it's an international package. She told us it's same thing, and we could drop it into the collection box. The online shipping label instruction reads, "international packages may NOT be placed in a USPS collection box. Customers must present such items to an employee at a Post Office regional service counter. The Postal Service will return improperly presented items to the sender for proper entry and acceptance." That's why I still think we cannot use a collection box for international packages, but we are used to sending packages to Japan, and we are pretty sure we calculate shipping fee and attach custom form correctly. As the USPS staff advised us, we will drop prepaid international packages into the collection box from now on.