IntermediatePROBLEM_SOLVING
During Petrol Pump Fuel Transaction Analysis, how did you validate the accuracy of reported daily sales and reconcile discrepancies between POS records and bank/payment provider records? Give a concrete example of a discrepancy you found and how you resolved it.
data analyst
General

Sample Answer

At a chain of 12 stations I worked with, I validated daily sales by cross-referencing POS logs, tank sensor volumes, and bank settlement files for a two-week period to establish baselines and expected variance (±0.5%). I wrote SQL queries to aggregate hourly POS transactions and matched them to acquirer settlement IDs, then compared net settled amounts to POS totals. One day showed a $3,400 shortfall (~2.8%) at a busy site: POS showed 1,120 liters sold but the bank settled only for 980 liters. I traced it to a firmware update that changed transaction batching and dropped 12 batched receipts during a cutover window. I coordinated with the payments provider and vendor, recovered stored transaction journals, reprocessed 140 transactions, and updated controls—adding an automated daily reconciliation script that caught similar issues within 2 hours, reducing unresolved discrepancies from 4% to under 0.2% monthly.

Keywords

Cross-referencing POS, tank sensors, and bank settlementsQuantifying discrepancy (amount and %)Identification of root cause (firmware/batching) and remediationImplemented automated reconciliation reducing unresolved issues