Cost allocation

Dear Expert,

We are working on the LSP scenario and have question on how cost allocation happens in ECC when the revenue and cost data is moved from SAP TM. Understanding is that Revenue data is moved through Forwarding settlement document and Cost data is moved through Freight Settlement document. Is this understanding correct. If yes, then what is the basis and how cost allocation will happens in ECC.

Thanks in advance

Thanks & Regards

Punit