How to Avoid Common Shipping Errors: A Guide for Shippers & Suppliers

A package shows up late, arrives damaged, or comes back with an extra fee nobody expected. A purchase order ships on time and still gets flagged short at the dock. Different symptoms, same root causes: wrong dimensions, incomplete documentation, mismatched labels, and missed windows.

This guide covers shipping errors from both sides. For parcel and freight shippers, that means the mistakes that turn into invoice corrections and denied claims with carriers like UPS and FedEx. For retail suppliers, that means the mistakes that turn into vendor scorecard hits and lost revenue with retailers like Walmart, Amazon, Target, and Kohl's.

What Counts as a Shipping Error

A shipping error is any mismatch between what a carrier or retailer's system expects on a shipment and what actually happens to it, from the dimensions entered on a label to the ASN transmitted before a truck leaves the dock.

Parcel and freight carriers catch these mismatches through automated scanning and billing systems that flag corrections after the package moves. Retailers catch them through automated receiving systems that flag deductions after the freight arrives. In both cases, no person reviews the flag before it turns into a charge.

Nearly every error, on either side, traces back to one of four root causes:

• Documentation

• Packaging and labeling

• Data accuracy (ASNs on the retail side, address and dimension data on the carrier side)

• Timing

1. Common Shipping Errors With UPS, FedEx, and Other Carriers

Parcel and freight carriers generate corrections and claim denials automatically, the same way retailers generate deductions, just through a different set of triggers.

• Address correction fees: Carriers charge a flat fee, often more than $20 per shipment, when their systems flag a delivery address as incomplete or invalid. A missing suite number, a typo in a street name, or a mismatched ZIP code all trigger it, even when the package still delivers correctly.
  

• Dimensional (DIM) weight corrections: UPS and FedEx both bill based on whichever is greater, actual weight or dimensional weight, calculated as length times width times height divided by a DIM factor (typically 139 for U.S. domestic shipments). Carriers scan packages at their own facilities and apply their own measurements. If your declared dimensions do not match what their scanners record, a correction lands on the invoice regardless of who measured correctly. Industry estimates put dimensional corrections on 5 to 12 percent of packages, averaging $2 to $6 each.
  

• Packaging and damage claims: Inadequate packaging, such as the wrong box strength for the item's weight, missing cushioning, or a reused box that has already lost structural integrity, leads directly to damage claims. Carriers require specific documentation to pay one: original packaging, photos of the damage, and proof of declared value.
  

• Freight classification errors (LTL): Freight carriers assign NMFC classes from 50 to 500 based on density and handling requirements. Misclassifying a shipment at booking triggers a reclassification fee once the carrier's own systems check it against the freight bill.
  

• Missed claim windows: Every carrier runs its own deadline, and missing it forfeits the claim regardless of merit.

Fix it:

• Weigh and measure every package with certified equipment, and feed those numbers into your shipping system automatically instead of entering them by hand.

• Standardize address validation at the point of order entry, before a label ever prints.

• Keep photos, original packaging, and proof-of-value documentation on file for any shipment carrying meaningful declared value.

• Audit UPS and FedEx invoices on a schedule. Billing errors follow predictable patterns once you know what to look for.

2. Documentation Errors and How to Fix Them

Documentation errors happen when the paperwork behind a shipment does not match the physical freight or the original order. The usual triggers on the retail vendor side:

• Purchase order, proof of delivery, and bill of lading data that do not line up

• Invoice quantities or pricing that drift from what actually shipped

• Cost changes that ship before they are effective in the retailer's item file

• Shipments confirmed against a canceled PO or a canceled line item

Documentation errors rarely happen in isolation. A single wrong quantity on a PO can cascade into an ASN mismatch, a shortage claim, and a compliance defect, all from one shipment. That compounding effect is why the same root cause often shows up under three different deduction codes. Our guide to common mistakes in deduction management covers how these errors spread across documentation, compliance, and oversight categories.

Fix it:

• Reconcile PO quantities against on-hand inventory before confirming any order.

• Confirm cost changes are live in the retailer's item file before the PO ships, not after.

• Store BOLs, PODs, and ASN records at the shipment level, timestamped, so they are ready if a dispute becomes necessary.
  

3. Packaging and Labeling Errors

Packaging and labeling errors are physical defects that stop automated receiving and force a shipment into manual handling, where miscounts and rework fees follow.

Walmart's automation-eligible case standards set a hard physical bar:

• Maximum 26"L x 20"W x 19"H

• Under 50 lbs

• Survives a 3-foot drop test

• No open flaps, loose shrink wrap, exposed tape, or obstructed barcodes

Barcode quality causes a disproportionate share of these failures. Cases need GS1-128 barcodes, pallets need SSCC-18 labels, and both need to scan cleanly at ANSI grade C or better. GS1 US publishes the standard case code labeling guidance that most major retailers reference for barcode structure and placement.

Amazon vendors see a similar pattern under different names: overweight cartons, mixed SKUs shipped in a case Amazon expected as single-SKU, and missing prep like poly-bagging for liquids or fragile items. Each one stops automated processing at the fulfillment center and generates a chargeback.

Fix it:

• Retest packaging whenever a SKU, pack size, or case configuration changes.

• Keep case markings (item number, description, supplier stock number) on more than one side of the case.

• Apply barcodes so they stay visible after shrink wrap and stretch wrap go on, not before.

4. ASN Errors: The Most Common Trigger

An Advance Ship Notice (ASN) is the electronic record a retailer's receiving system checks the physical shipment against before it accepts the freight. When the ASN is missing, late, or does not match what arrived, the system cannot reconcile the shipment automatically and diverts it to manual receiving, where miscounts generate shortage claims even when the full order arrived intact. The system compares data first and freight second, so a shipment can arrive complete and still get flagged the moment the ASN quantities or timestamps do not line up.

Walmart classifies ASN failures under its SQEP "Right Invoice" category, its second-largest source of fines after packaging defects. Kohl's tracks ASN errors under specific reason codes:

• ASN08: incorrect vendor ship date

• ASN11: wrong DC or store listed on the notice

Amazon vendors see the same failure mode when an ASN transmits after the shipment has already left the origin facility. Manual ASN creation is the largest single source of these errors across every retailer. Our full breakdown of Advance Shipment Notices covers the required data fields and retailer-specific formatting rules in more detail.

Fix it:

• Integrate your WMS or ERP directly with your EDI provider, so ASNs generate automatically instead of manually.

• Transmit the ASN before the shipment departs, never after.

• Verify SSCC labels are present on every pallet listed in the ASN, and that quantities match the physical shipment exactly.

5. Retail Carrier Assignment and Timing Errors

Timing errors happen when a shipment leaves too early, arrives too late, or moves on a carrier the retailer did not assign.

• Walmart: Calculates its Must Arrive By Date (MABD) as the Do Not Ship Before date plus in-transit days. Miss that window in either direction, and Walmart issues a deduction: Code 64 for early shipments, Code 65 for late ones. Early arrivals are not automatically safe. They disrupt Walmart's just-in-time receiving flow and can fail the on-time metric just as easily as a late one.
  

• Amazon: Measures timing differently depending on who controls the freight. Collect shipments are held to a Freight Ready Date, the window during which freight must be staged for pickup. Prepaid shipments are measured against a Carrier Requested Delivery Date at the fulfillment center. Missing either window triggers an automatic chargeback, and using an unapproved carrier is treated as a routing violation on top of it, even if the freight arrives on time.

Fix it:

• Build a one-day transit buffer into routing plans for distant DCs.

• Confirm POs only when the product is physically available to ship by the required date.

• Never substitute your own carrier to beat a delayed pickup appointment. Open a ticket with the retailer instead.

• Do not touch shipment dates in the retailer's system while a load is already in routing.

Our guide to vendor routing requirements walks through carrier assignment and booking windows retailer by retailer.

Retailer-Specific Rules Worth Knowing

The categories above show up at every retailer, but the thresholds, codes, and enforcement points differ enough that a supplier shipping to three or four retailers needs to track each one separately.

Walmart's OTIF performance metrics and SQEP compliance checklist go deeper into how these thresholds get measured and disputed if you sell into Walmart specifically.

A Pre-Shipment Checklist to Catch Errors Before They Ship

For parcel and freight shippers:

• Weigh and measure every package with certified, calibrated equipment before it ships.

• Validate delivery addresses at order entry, not at label creation.

• Match packaging strength and cushioning to the item's weight and fragility.

• Confirm the correct freight class before booking an LTL shipment.

• Photograph packaging and contents for any shipment carrying meaningful declared value.

• Review carrier invoices on a set schedule instead of only when something looks obviously wrong.

For retail vendor compliance:

• Confirm PO quantities against actual on-hand inventory before confirming the order.

• Verify the ship and arrival window (MABD, Freight Ready Date, or the retailer's equivalent) lines up with your ship point's real transit time.

• Print barcodes at a readable grade and check placement on at least two sides of each case.

• Match case count, pallet count, and PO documentation before the trailer leaves the dock.

• Transmit the ASN before the shipment departs, not after.

• Use only the carrier the retailer assigned through its routing system.

What to Do When a Shipping Error Already Triggered a Claim or Deduction

A charge tied to a shipping error is not automatically valid, whether it is a UPS DIM weight correction or a Walmart SQEP fine. Disputes succeed most often when the error traces back to the carrier or retailer's own system: a data entry mistake, a scanning error, a misapplied fee. Disputes on genuine, documented failures rarely succeed, because the pass criteria are built to be unambiguous.

Three things matter for a dispute to hold up, on either side:

• The right documentation: Proof of delivery, signed BOLs, carrier appointment confirmations, and photos for damage claims need to match the disputed amount to the exact figure. For SQEP disputes specifically, Walmart rejects any submission that misses the backup total by even a cent.
  

• The right window: Walmart gives 30 days for OTIF disputes through APDP, 90 days for returns billing claims, and up to 13 months for SQEP fines through EIPP. UPS gives up to 180 business days for parcel claims. Amazon, Target, Kohl's, and every freight carrier run their own windows and portals.
  

• The right root cause: A dispute filed under the wrong reason code, or a claim missing the required backup document type, gets denied automatically, regardless of merit.

Tracking deadlines and documentation across multiple carriers and retailers at once is where most valid disputes get missed rather than lost on the merits. iNymbus automates that matching process on both sides: it pulls deduction and claim data directly from retailer and carrier portals, matches it against your shipping records, PODs, and BOLs, and files inside the required window across more than 50 retailer and carrier portals, including Walmart, Amazon, Target, Kohl's, UPS, and FedEx.

Stop Losing Revenue to Preventable Shipping Errors

Shipping errors, whether they show up as a parcel invoice correction or a retail vendor deduction, are the most preventable category of shipping cost and also the easiest to lose track of at volume. The fixes above address the root causes on both sides. For the charges that already landed, iNymbus automates the recovery process end to end for retail deductions and carrier freight claims alike, so recoverable revenue does not become a permanent write-off.

Schedule a demo with the iNymbus team to see how it works for your shipping operation.