Need different line for detention at each stop at sell shipment

Summary:

In a multileg scenario, we have multiple buy shipments for 1 order release and on buy shipments with mode TL we have detention charges, so we are adding a new cost line in shipment cost after some events, we have multiple buy shipments with detention at different stops, and we are calculating base carrier free minutes and charges, so we want to have calculation at sell shipment based on customer free minutes and charges. Right now we are doing in below way

For example

Order Release - OR1

Buy Shipments - B1 (TL), B2 (RAIL), B3 (TL)

We have detention of 60 mins at 1st stop of B1 and detention of 400 mins at 2nd stop of B3