Subscriptions - Adjustments

This API allows customers to create and mange their subscriptions for any adjustments on their packages.  This also includes the listener URL specifications for the webhook to receive adjustment event notifications per package.

Adjustments are any changes or discrepancies detected in the mailstream against a package's manifested characteristics that affect the package's pricing.  For example, if a package was manifested with one weight and mailed with another, an adjustment may be issued for the difference in pricing.