I went to mail a slightly oversize envelope, the dimensions of which are 4 11/16" x 9 15/16" ; under 1/4" thick and weight 0.6 oz. By every guideline I could find on the USPS web sites this should have been eligible for the standard letter rate. But I was charged the extra $0.21 for an oversize envelope. Today I called the USPS customer service line (1hr 10 min on hold), and asked for clarification. I was told that the standard rate applied to minimum-size 3.5" x 5" envelopes, and that anything larger got surcharged. If that is correct, than a standard #10 business envelope of 4 1/8" x 9 1/2" inches might cost more than the (currently $0.50) first class rate, which I’m certain can’t be the case.
I’m majorly confused. I’ll pay whatever the USPS legitimately charges but now I have no idea what counts as oversize and what doesn’t. Can anyone give me the Straight Dope on this?