Not only that but I think they changed their standards without notice. Their web site used to say that if you had an envelope that was too fat to meet the 1/4" thick designation you could then call it a large envelope and it could be up to 3/4" thick. Now they have added minimum dimensions to the large envelope description so a regular envelope no longer qualifies. This means that any fat regualr envelope now becomes the most expensive category - that of a package.