The manager at the USPS' Mailing Requirements Office for our area contacted me to give me the list of cities that you can ship from. We weren't on it, so I didn't really pay too much attention to the rest. You can contact the Mailing Requirements Office in your area, and they should be able to point you in the right direction... if they don't feel like it's too much work. I've found that I had to fill them in because they didn't know any of the details until I told them. Then they could look for more answers. If you don't tell them everything, they will take a few days to get back to you, only to tell you what you already know, so be thorough.