The challenge
Most TDS defaults only become visible after filing, when the Justification Report arrives from TRACES and the deductor has to file a correction and sometimes pay interest or late fees.
What we built
We studied the justification reports of live returns to see which defaults actually occur, then built a Windows program that reads the return file itself - 26Q and 27Q - and produces an Excel forecast of the notices likely to follow: wrong or short deduction rates, short or late payments, PAN and name mismatches, challan allocation problems. Section rates, thresholds and certificate details sit in an editable settings file, so the checks follow the law rather than a fixed table. Checks that need outside data, such as PAN-Aadhaar status or challan balances already used in other returns, are not guessed; the report warns only where the file itself shows a risk. Corrections are made first and the return is filed clean the first time.
The result
Before: defaults found after filing. Now: filed clean first time.