Use the ReducedTotals Extension to model this information.

Elements

Element	Description
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ ReducedTotals/TaxTotal/TaxSubtotal/TaxableAmount`	Specifies the difference between the taxable amount of the current invoice and the taxable amount of the preceding, corresponding advance payment invoice for a given Tax Category, in the final invoice.
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ ReducedTotals/TaxTotal/TaxSubtotal/TaxAmount`	Specifies the difference between the tax amount of the current invoice and the tax amount of the preceding, corresponding advance payment invoice for a given Tax Category, in the final invoice.
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ ReducedTotals/TaxTotal/TaxSubtotal/TaxCategory`	Specifies information about the tax category for each tax breakdown of the current and of the preceding, corresponding advance payment invoice, in the final invoice.
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ ReducedTotals/TaxTotal/TaxSubtotal/TaxCategory/TaxScheme/ID`	Specify `VAT`.

Restrictions

You must specify VAT in the TaxScheme element.
You must use one of the following values for the TaxCategory element. These values are derived from the UNCL5305 list.

Value	Description
`S`	Standard rate
`AE`	Reverse Charge
`Z`	Zero rated goods/tax exemption with right to deduction
`E`	Exempt from VAT/tax exemption without deduction rights
`R`	Exempt from VAT
`O`	Services outside scope of VAT
`OE`	Services outside scope of VAT 2
`SS`	Special procedures
`N`	Cancellation

Example

<ubl:Invoice>
    <cec:UBLExtensions>
        <cec:UBLExtension>
            <cec:ExtensionContent>
                <vrbl:InvoiceExtension>
                    <!-- Code omitted for clarity -->
                    <vrbl:ReducedTotals>
                        <cac:TaxTotal>
                            <cbc:TaxAmount currencyID="RSD">110</cbc:TaxAmount>
                            <cac:TaxSubtotal>
                                <cbc:TaxableAmount currencyID="RSD">400</cbc:TaxableAmount>
                                <cbc:TaxAmount currencyID="RSD">80</cbc:TaxAmount>
                                <cac:TaxCategory>
                                    <cbc:ID>S</cbc:ID>
                                    <cbc:Percent>20</cbc:Percent>
                                    <cac:TaxScheme>
                                        <cbc:ID>VAT</cbc:ID>
                                    </cac:TaxScheme>
                                </cac:TaxCategory>
                            </cac:TaxSubtotal>>
                            <!-- Code omitted for clarity -->
                        <cac:TaxTotal>
                    </vrbl:ReducedTotals>
                    <!-- Code omitted for clarity -->    
                </vrbl:InvoiceExtension>
            </cec:ExtensionContent>
        </cec:UBLExtension>    
    </cec:UBLExtensions>
    <!-- Code omitted for clarity -->
</ubl:Invoice>