Double-Dip Detective: Finding Duplicate Deductions

One deduction is painful.

Two for the same issue? That’s a margin leak with a trench coat on.

Duplicate deductions usually aren’t malicious. They’re procedural. Multiple systems, multiple teams, and multiple “reasons” can get attached to the same underlying event—especially when disputes are rushed, and documentation is scattered.

And the backdrop matters: in Attain Consulting Group’s 2021 Customer Deduction

Survey, the median non-trade-related deductions (compliance + shortages) were ½–1% of sales, and the median “Days Deductions Outstanding” (Days Deductions Outstanding, or DDO) was 39 days. Even if you’re “only” at ½–1%, that’s real money at scale.

Worse: the same survey reports the median share of deduction dollars that are invalid is 5.1–10%, and the median recovery of those invalid amounts is 60%. Translation: some invalid deductions never come back. And duplicates live in that bucket.

A fictional “double-dip” you’ll recognize

Fictional example (not a real supplier):A supplier gets a shortage deduction on an invoice. They dispute it with proof of delivery (POD). Weeks later, a second deduction hits—same amount—coded as a compliance fine tied to “documentation missing.” Nothing new happened. The same event got billed twice under two labels.

This is why duplicate detection has to be systematic, not accidental.

The 5 most common duplicate patterns

1. Shortage + compliance on the same shipment

2. Return + defectives double-counting the same units

3. Pricing claim + promo/allowance mismatch on the same invoice

4. Unearned discount + short pay for the same payment

5. Rebill/credit loop where the correction triggers another deduction

(If you’ve ever seen the same $487.23 appear twice, months apart, you know exactly what we mean.)

Your Duplicate Deduction “Fingerprint”

To find duplicates quickly, you need a fingerprint stronger than “invoice number.”

Capture these fields in your deduction register:

• Retailer

• Amount

• Deduction code/reason

• Invoice number + purchase order (PO)

• Ship date + delivery date

• Distribution center (DC)/store number

• Stock keeping unit (SKU)/item number

• Claim reference ID (portal ID, case ID)

Duplicates hide when one of these fields changes—but the core fingerprint (amount + item + date window + node) stays the same.

Matching rules that work in the real world

Use three passes:

Pass 1: Exact match

• same retailer + same amount + same SKU + same date window (e.g., 30 days)

Pass 2: Near match

• same retailer + amount within a tight tolerance (e.g., ±1–2%) + same PO/DC window

Pass 3: “Same story, different code”

• same retailer + same amount + different code within a short window after a dispute is filed

Near matches catch cases where freight, tax, or per-unit rounding changes the number just enough to hide a dupe.

The weekly “Double-Dip” routine (45 minutes)

This is the habit that pays you back.

1. Pull top repeats by amount and by SKU

2. Sort by open age (watch deadlines)

3. Review “resolved” items that reappeared

4. Assign owners and set a next action date

5. Log outcomes so you don’t fight the same case twice

You’re not building a perfect system. You’re building a system that catches the easy money.

Quick win checklist: What to check first

•  Same amount appears twice within 60 days

•  Same amount tied to two different reason codes

•  Deductions that hit immediately after a dispute win

•  Returns/defectives spikes that coincide with packaging or carrier changes

•  “Documentation missing” codes when you know documentation exists (usually a mapping or portal issue)

Where HRG fits

Duplicate deductions are a classic “small leak, big bucket” problem. If you’re already stretched, the duplicates are the first thing you miss—and the easiest thing to recover once you have a repeatable process.

HRG often helps by building the fingerprint logic, tightening proof packages, and making the weekly routine stick.

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