Yes. In most cases, any negotiated rates you have with your carrier will automatically appear as the rate in ShipStation.
For FedEx accounts with negotiated rates, the rates will appear only after you have created your first label in ShipStation.
For UPS accounts, you must enable negotiated rates in ShipStation first. Go to
Settings > Shipping > Carriers & Fulfillment. Click Settings and then check the Enable Negotiated Rates option. Then, click Confirm.
At this time, ShipStation does not automatically select the service with the cheapest rate. To compare rates, use the Rate Calculator.
The most common reasons you would see different rates in ShipStation are because:
There is a mismatch between shipment details on ShipStation and your carrier website.
You have not enabled negotiated rates in ShipStation.
For help troubleshooting this issue, please review the Rate Discrepancies article in our Troubleshooting Help guide.
ShipStation does not currently send rates to your selling channel for your customers to select on checkout. ShipStation received the orders only after the check out is complete. Many selling channels offer plug-ins you can connect your carrier accounts to that will display live rates to your customers at checkout. If you connect the same carriers to your selling channels as you connect to ShipStation, the live rates provided should be very similar.
At this time, ShipStation does not send live rates to your selling channels for your customers to select at checkout. Most selling channels provide access to plug-ins so you can provide live rates from your carrier account to your customers during the checkout process. You will need to contact your selling channel for details.