USPS Merchant Rates

A USPS representative just contacted our company. This representative said we should switch shipping platforms and use GrandShipper because they offer USPS Merchant Rates and ShipStation does not. When will ShipStation offer Merchant Rates for USPS Priority Mail packages?

https://usps.my.salesforce.com/sfc/p/#j0000000GyYH/a/t0000002lr9Y/gpV98CU4BvHuLc4yRS.1adZwHiP.4FknKbcTMctnerM