A receipt contains a transaction number, loyalty identifier, subtotal, tax, and final total. The recogniser reads every character. The application then selects the number nearest a familiar label, but glare has shifted the detected region and the label belongs to the line above. The output is fluent, properly formatted, and wrong.
That failure is easy to miss when success is reported as a page-level accuracy percentage. The buyer does not need every character equally. They need the correct merchant, date, identifier, amount, or line item attached to the correct field, in the format the receiving system accepts. A single false acceptance can matter more than a hundred harmless punctuation errors.
Production OCR therefore starts before recognition and ends after it. Capture quality, page orientation, layout, vocabulary, normalisation, validation, source coordinates, thresholds, and review determine whether a model output becomes a useful product capability or another queue people quietly recheck.