AGL vs Partnered Carrier (Send) Shipment Plans

Hello Everyone,

We are moving away from our previous utilized Freight Forwarder and are now looking at options with Amazon directly.

As I understand it, AGL is full service where I need to create an IOR profile and can select shipments this way. From there, Amazon handles everything and sends me the bill after I confirm the shipment plan.

How does this different from Send (Partnered Carrier). This looks to be similar in that I create the shipment plan to AWD and it gives me several options to choose from (LinkTrans, Forest etc). How is Customs handled? Do I need to create an IOR Profile on this option as well? or Do I handle Customs with my own Broker? I am struggling getting the IOR Profile (keeps throwing an error when trying to submit the application and am getting no help from seller support) to work and am in a rush to get a shipment chosen (to get this in before the 90 days are over)

TLDR: In Send (Amazon Partnered Carrier) shipment plans, do I handle customs on my own with a Broker of my choosing? Or do I need to still go through Amazon like a full AGL plan? Thanks.