Possibly it's different for business mailings? I don't know so I won't pretend to. I do recall a job many years ago in which I did some advertising work for a small company, we did some flyer mail outs, and it was difficult dealing with the post office for that. Otherwise in personal use I've never ran into any issues like this. I know I receive plenty of stuff in the mail via USPS, and most of it comes fairly quickly. They surprise me sometime how fast they get stuff across the country from one place to another.