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FirstBIT ERP calculates the balances of the Current Tax Payable and Current Tax Receivable accounts and then calculates the difference between the balances. If the resulting amount is greater than zero, then the difference is shown in the document as VAT Payable —that is, the tax amount to be paid to the Tax Authority.
If the resulting amount is a negative value, then the document shows it as VAT Receivable —that is, the refundable amount that the Tax Authority may return to the taxpayer. This refundable tax amount can be received upon request or it can be carried forward to a subsequent tax period or multiple subsequent periods to be offset against payable tax or any penalties imposed.
In a new document of the Calculation of VAT Liability type, you need to fill in the required On Date field in the upper area of form. 
The "Calculation of VAT Liability (Create)" form
In the On Date field, specify a date that indicates the end of period for which the tax information will be collected and processed.
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