Running in parallel means that for one payroll period, you calculate payroll in both places and then compare the results. It costs about one extra working day, but in return you can be sure no one is paid incorrectly.
Schedule for a parallel run period
| When | Task |
|---|---|
| Start of the period | Notify employees: starting today, clock in and submit requests on Tanca, but this period's payroll will still be calculated the old way |
| During the period | Employees use Tanca for real; HR keeps parallel records the old way |
| End of the period | Finalize the timesheet on Tanca, and complete the old timesheet at the same time |
| After finalizing | Run the payroll period on Tanca and compare it with the old payroll |
| Before payday | Pay salaries according to the old payroll; use the Tanca payroll only for reconciliation |
Compare at four levels
- Total payroll — aim for a difference of less than 1%.
- Totals by department — shows which department has a problem.
- Each person in the department with the largest difference — narrows it down to a few profiles.
- Each line of that profile — finds which item is wrong.
Common causes of discrepancies
| Where the discrepancy is | Common cause | Where to fix it |
|---|---|---|
| Working days | Missing shifts in setup, different rounding rules | Time & Attendance › Settings |
| Overtime | Incorrect overtime multipliers | Time & Attendance › Settings › Overtime |
| Leave days | Incorrect beginning-of-year leave balance | Requests › Settings › Leave |
| Allowances | An item is missing from the payroll template | Payroll › Payroll Template |
| Insurance and tax | Incorrect insurance contribution salary | HR › Insurance |
| New hires, mid-period leavers | Incorrect start date or termination date | Employee profile |
Only stop running in parallel when the two payrolls match at the individual level, not just in total. Matching totals with individual discrepancies means there are two errors canceling each other out — they will surface next month.
When you don't need to run in parallel
Businesses with fewer than 20 people, a simple salary structure and no complex overtime can skip it and just carefully reconcile the three trickiest profiles as described in article A2-08.
