Accessorial charges are amounts billed in addition to base freight that compensate extraordinary transportation services or conditions —handling, detention, reconsignment, dry runs, storage— and must be authorized, documented and, in Mexico, invoiced with the corresponding SAT (Servicio de Administración Tributaria) code.
Base freight looked cheap; then came origin handling, two hours of detention, reconsignment for a dock change, and a dry run. All-in rose ~18%. Accessorials are not the enemy; opacity is. This guide covers definition, the SAT matrix, five-step control, and the cost hedge when rules are missing.
- of shipment cost when uncontrolled (hedge)
- 8–20%
- typical recoverable leakage in 100% audit
- 5–7%
- code by service — not only 78101800
- SAT
- accessorial lines to audit (no sampling)
- 100%
Cluster: distribution KPIs · detention · freight audit · accessorials guide · SAT code finder.
What accessorials are (usable answer)
Base freight covers the agreed move under normal assumptions (origin, destination, equipment, window). An accessorial covers what falls outside those assumptions: extra plant time, additional physical work, destination changes, empty miles attributable to the shipper, and similar extras.
In freight-audit practice (CSCMP / North American freight payment), accessorials are where leakage concentrates when shippers only control linehaul. In Mexico the pattern worsens: WhatsApp as “authorization,” stamped CFDI without evidence, and tendering that awards on base price alone.
The boundary matters: if everything is accessorial, you have no rate; if nothing is accessorial, you subsidize exceptions. The contract (or rate card) should list concepts, rates or formulas, free time, and minimum evidence.
Accessorials in Mexico and SAT codes
Invoicing everything as generic freight (78101800) is a fiscal and operational error. The c_ClaveProdServ catalog separates services: 78121601 (loading/unloading), 78121500 (packing), 78111800 (storage), 78141500 (fleet management), among others. Mixing them on one line breaks rate–invoice matching and cost analytics.
Before stamping or auditing, verify the concept in the SAT code finder. A wrong code is not only SAT risk: it makes line-by-line audit impossible. Pair with how to invoice freight and accessorials.
Handling / load-unload
What triggers billing: Extra physical work agreed
Minimum evidence: POD + authorization
SAT note: Specific service code
What triggers billing: Plant time > free time
Minimum evidence: GPS / dock timestamps
SAT note: Do not confuse with demurrage
Dry run / falso flete
What triggers billing: Failed trip attributable
Minimum evidence: Order + documented refusal
SAT note: Separate from freight
Reconsignment
What triggers billing: Destination / dock change
Minimum evidence: Written instruction
SAT note: Recalculate segment
Layover
What triggers billing: Authorized overnight wait
Minimum evidence: Log + agreement
SAT note: Clear contract rule
How to control accessorials in 5 steps
Control happens before pay: clear rules prevent the accounts payable fight; fighting the invoice always arrives late.
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Publish catalog
Step 1
How much they weigh in shipment cost
When tendering only looks at base price, the stack of handling + detention + extras can move 8–20% of total shipment cost. Treat it as an operational hedge: calibrate by industry, lane, and appointment discipline — not as a universal law.
In 100% audit, the recurring pattern is recovering on the order of 5–7% leakage in poorly supported lines (reference from the 3PL case). If accessorials today live only in the carrier’s narrative, you are in the pattern TMS vs agents attack in the trip file.
For the cash and distribution cost board, use the hub distribution KPIs — logistics Mexico.
Myths that leave spend out of control
If your team repeats these myths, spend is already out of control.
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Do not assume “inevitable carrier cost”
Accessorials and service travel together: OTIF (On Time In Full).
OCL and the trip file
OCL Cargo is an autonomous transportation management system (TMS) with agents: it joins rate catalogs, authorizations, proof of delivery (POD), and documents in a trip file so the accessorial can be defended or rejected — not invented in Excel. It coexists with your system of record; your team decides exceptions. When applicable, OCL can stamp invoices and Carta Porte. It does not guarantee an accessorial percentage or replace your contractual policy.
Key takeaways6 points
- Accessorials = charges on top of base freight (handling, detention, reconsignment, dry run, storage) that must be authorized and documented.
- In Mexico: invoice with the correct SAT (tax authority) service code; not everything fits under generic road freight 78101800.
- Without a contractual catalog and prior authorization, the accessorial becomes an endless accounts payable dispute.
- Uncontrolled, they can move 8–20% of total shipment cost when tendering only looked at base price — calibrate by lane.
- Audit 100% of accessorial lines (no sampling). Hub: distribution KPIs.
- Time sibling: what is detention. Operating guide: accessorials for shippers and 3PLs.
Do your accessorials have rules… or only show up on the invoice?
Related reading
Frequently asked questions
They are sometimes used interchangeably. In practice, an accessorial is usually a specific service or condition (handling, detention, reconsignment); a surcharge (fuel, peak) is a percent or fixed adjustment on freight. Treat them as distinct lines in contract and CFDI (Mexican electronic invoice).
Often 78121601 (loading/unloading) or others depending on the exact service. Confirm in the SAT code finder with the real work description.
Yes in a broad sense: it is an add-on to base freight for vehicle/driver dwell beyond free time. Control it with free time, hourly rates, and timestamps. Detail in what is detention.
RFQ template with assumptions and mandatory breakdown; all-in award; real-time authorization if something arises outside the brief. See spot vs contract.
It varies by industry and discipline. With weak controls, 8–20% of total shipment cost is not rare when handling + detention + extras stack — operational hedge, calibrate by lane. Compare to the typical 5–7% recoverable leakage in 100% audit.
Not automatically. Stamped ≠ authorized. Freight audit separates fiscal form from operational substance: contractual catalog + evidence (proof of delivery / GPS) before accounts payable releases.
Yes: in tendering (compare all-in), tracking (time/event evidence), and 100% line audit. The 3PL case is the recovery reference.