Make certain settings fields not required;
Some client's may want to offer free shipping only, in which case they have no need for the
USPS WebTools API User Id or UPS settings
Perhaps add some multi-select to allow users to configure which shipping methods they want to use, and if USPS or UPS are not selected, do not require configuration data to be present in those fields?
Likewise if certain shipping methods are not enabled do not show them in the Calculation Method dropdown?
Make certain settings fields not required;
Some client's may want to offer free shipping only, in which case they have no need for the
USPS WebTools API User Id or UPS settings
Perhaps add some multi-select to allow users to configure which shipping methods they want to use, and if USPS or UPS are not selected, do not require configuration data to be present in those fields?
Likewise if certain shipping methods are not enabled do not show them in the Calculation Method dropdown?