Suggestion:
In Despatch, item details, system has a provision to set the line items from Sales order as it is to despatch.
In Despatch, after entering the Sales order number and header details, users can click on next to enter the item details. In the item details screen on the subheader horizontal panel there is a ‘Default’ button. Users can click the default button instead of clicking on the add button and once default is clicked the system adds all the line items with all its item details, which are saved in the Sales order mentioned in the header page. Users do not have to add the lines manually, the system does the same automatically. Then the user can click on the finish button to finish the despatch.
Please refer to the snapshot below: Default