Weighing stop, multi-stop and customs stop all relate to the same thing in road transport: an additional processing address.
Normally, transport moves from loading location A to unloading location B. However, the client often demands additional activities for the cargo. This may include the determination of the laden weight in the event of different bulk products, or complying with customs-related obligations.
As the transport price is usually tailored to just transport from A to B, the additional costs of this additional stop are covered by the multi-stop. Regular multi-stop costs are based on an en-route stop.