Cargo may be consolidated by an Agent. For example, if agent have some customers who have shipments to a certain destination, agent can issue separate House Air Waybill (HAWB) for each customer and then issue one MAWB for the whole shipment.
This way, the bigger weight will be reflected on the MAWB and lower freight charge for the whole shipment will be paid to the airline while Agent is receiving the applicable rate per weight of each consignment and will benefit from difference in the rates.
There is also possible for the agent to make more money at destination. The representative of the agent will pay for one delivery order (DO) charge to the airline and receive the DO charge for all the issued HAWBs, from consignees.