Product · TDS & TCS
The section and rate are decided when the bill is recorded, not rebuilt from memory in the last week of the quarter — and the deduction is tracked all the way to the challan.
A section chosen at entry is cheap; the same section reconstructed in the last week of the quarter is expensive. Autobooks applies it where the transaction happens and carries it through to the challan.
All the way to the challan, without a spreadsheet.