Price the extra parcel before changing warehouse routing

A warehouse may be close to the customer but hold only part of the basket. Sending the remaining item from another location can add a second pick, package and delivery charge. Compare the complete set of shipments required under each feasible route. The cheapest individual label is not necessarily the cheapest way to fulfill the customer order.

Shopify's routing documentation describes rules that minimize split fulfillment, stay within the destination market and prioritize proximity. Rules run in sequence. Review the actual rule order and available inventory at the order time before treating an unexpected warehouse assignment as a fault or assuming proximity alone determines the result.

For each option, include warehouse handling, packaging, transport and any genuine additional fees. Use the contracted service and expected parcel characteristics. Compare a single shipment, split shipments and a transfer followed by consolidated fulfillment only where each option can meet the customer promise. A theoretical low-cost route is irrelevant if it cannot dispatch in time.

In a hypothetical order, one warehouse can fulfill the whole basket for $14 of handling and shipping. Splitting it produces parcels costing $8 and $9, for a total of $17. The split reduces contribution by $3 before any additional customer-service cost. If consolidation first requires a $5 transfer, that alternative costs $19 rather than $14.

Keep customer revenue at the order level while allocating or associating fulfillment costs for analysis. Copying the entire order sale onto each parcel doubles revenue in a two-shipment order and makes both warehouses appear profitable. The shipment schedule should reconcile back to one customer order and its actual total cost.

Classify observed splits by cause: inventory distribution, stock inaccuracies, product restrictions, routing priorities or an approved service exception. Preserve the inventory snapshot and rule configuration relevant to the decision. Looking at today's stock may suggest a single warehouse could have fulfilled an order even though that stock arrived after the order was assigned.

Review avoidable causes separately from legitimate customer choices. Repeated splits for a common basket may justify replenishing complementary products together. A split caused by an urgent delivery commitment may be commercially reasonable. The useful measure is cost against a feasible alternative, not a blanket target to eliminate every multi-parcel order.

Use a bounded sample of orders to compare the proposed rule with the current approach. Track total fulfillment cost, dispatch performance, cancellations and manual overrides. Include the orders that could not be routed as planned. A change that saves postage but creates stockouts or missed commitments needs a broader assessment before expansion.

Document the approved priorities and the circumstances that permit an override. Give warehouse staff a way to record the reason for a manual move so finance can distinguish configuration behavior from operational intervention. After final carrier and warehouse charges arrive, compare actual savings with the original estimate and update the assumptions used for the next routing decision.