Método de envío por USPS

We’d like for packages marked as letter/envelopes to include media mail quotes. Sometimes envelopes are too heavy for first class rates, so the only rates returned are priority mail, when the package is actually eligible for media mail.

This can be implemented by modifying the USPS API request to ask for package and envelope rates in the same request (only when the package is an envelope) and displaying the lowest rates from both.