USPS Module not returning values for Domestic 1st Class Lg Envelope

[coskier]

Force the machinable by adding this code:

        default:
          // admin choice on what to use
          $this->machinable = MODULE_SHIPPING_USPS_MACHINABLE;
      }
          $this->machinable = MODULE_SHIPPING_USPS_MACHINABLE;

      // What method to use for calculating display of transit times

That seems to have done the trick, thank you!