Recovering 64,300 zł from Erroneous Invoices at a Parts Distributor
We analyzed 12,480 invoice items at a local distributor. We found a systematic error in calculating supplier discounts that had lasted for 19 months.
In March 2024, we entered the office of Autoczęści Radomski S.C. The owner felt that margin was leaking out the side, but didn't have time to manually check hundreds of pages of documents. We dug through the purchase history and found specific money that belonged to the company.
The challenge
The company serves 487 regular workshops and buys goods from 14 large suppliers. For the last 19 months, the accounting system incorrectly calculated discounts from one of the key contractors. Manually checking 12,480 invoice items exceeded the capacity of the two-person accounting department. Losses grew quietly because no one had the tools to quickly catch differences in purchase prices.
The owner knew something was wrong with profitability but lacked hard evidence for a complaint. Every mistake on an invoice was a loss of 5 to 45 zlotys, which at this scale produced a significant sum.
Our approach
Dariusz Mazur along with an analyst pulled raw data directly from the client's SQL database. We didn't do boring meetings about vision. Instead, for the first 11 business days, we built a script that automatically compared prices from supplier PDF price lists with actual purchase invoices.
We focused on the 'braking systems and suspension' product group, where turnover was highest. We checked every document from the last two years, looking for discrepancies larger than 0.5%. We worked in the background so as not to disturb the team in their daily parts sales.
The solution
We built a simple report in Power BI that shows red flags for invoices with incorrect prices every Tuesday at 9:00 AM. The system automatically calculates the overpayment value and generates a ready-made attachment for a correction request.
We trained Ms. Beata from accounting in 2h 15min. Now one click is enough to see which supplier is trying to charge too much. They didn't have to change their warehouse program – our tool works alongside and pulls data without staff effort.
Results
Within seven weeks, the company recovered the full amount of overpayments. After receiving our reports, the supplier admitted the error in their system and issued corrections for a total of 64,317 zł. That much really stayed in the client's pocket.
Timeline
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04.03.2024Initial audit and export of 12,480 items from the SQL database
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15.03.2024Detection of a systematic error in supplier discounts
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28.03.2024Sending the first 14 batches of complaint documents to the supplier
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12.04.2024Power BI report implementation and accounting training
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24.04.2024Booking the last correction to the company's account
"I was afraid the audit would block our work for a month and nothing would come of it. Logika i Wynik took care of it themselves, and after 11 days I got a list of specific money to recover. Numbers don't lie."