If the program does not calculate IIT for an employee, the most common reason is a carried-over deduction — it "carries over" from the previous period and affects the tax calculation for the current month.
Why this happens
An employee may have an unused deduction remaining from the previous period (for example, if the income was less than the amount of the eligible deduction). Such a deduction does not disappear, but carries over to the next month and reduces the taxable base. Because of this, if the income amount in the current period is insufficient, IIT may not be calculated at all or may be calculated in a smaller amount than expected.
What needs to be done
Check the employee's accruals for previous periods — whether the deduction was applied in full or a carried-over portion remained. If the deduction has indeed carried over, this is a normal situation, and IIT in the current month will be reduced or not accrued by the amount of this deduction. Make sure that the employee's deduction and income data are entered correctly and consistently by month — then the IIT calculation will proceed correctly, taking into account the carried-over amounts.
Frequently Asked Questions
Is this a program error?
No, this is a feature of the deduction calculation mechanism — deductions can carry over to the next period if they were not fully used earlier.
Do I need to correct anything manually?
Generally, no — if the employee's data is entered correctly, the program will automatically take the carried-over deduction into account in the calculation.