Jan 22 USPS price change seems to also have changed the names of a couple shipping types from Package to Parcel.
See USPS methods support thread around page 60
We do not offer USPS first Class domestic so I cannot speak to the issues described on the tread relating to missing handling charges, one poster comments
"OK, for those who lost their handling charge on First Class Package (Parcel), there's a string that has to be replaced around the middle of the usps.php file:
Change "case 'First-Class Mail Package':" to "case 'First-Class Mail Parcel':". This worked for me and the handling charge is now added in. Look for the "$postage = $postage + $this->handling;" string. The case statement for 'First-Class Mail Package' is about 30 lines below that. "
I do confirm editing catalog/includes/modules/shipping/usps.php
'First-Class Mail Int Package' => 'First-Class Mail International Package**',
'First-Class Mail Int Package' => 'First-Class Mail International Parcel**',
resolves the issue with first class international not being displayed as a shipping option.
configure store to offer USPS first Class international as a shipping option with store location based in United States.
Login as a customer with an international address.
proceed through checkout, other options are available but First Class International is not.