...
The tab provides information only on those loans borrowed by the employee that have non-zero interest and are paid monthly. Lump-sum loans appear on the tab in the period of their repayment date if they were registered with non-zero interest – the interest amount will be calculated here.
The interest amount to be paid for the current month of work (pay period) is calculated when you click Calculate on the toolbar. The amount appears as a deduction on the Accruals and Deductions tab.
The "Payroll Calculation (create)" form. The Loans tab
...
The Percentage Payment Amount column shows for each loan the amount of interest for the current month which is calculated as follows: Loan_Amount LoanAmount *P(%)/(100*12).
The Income Item column shows the income items specified for each of the loans with interest.
...