The Problem
When having a SubInvoiceLine, with InvoicedQuantity = 0 and therefore LineExtensionAmount = 0, the validator returns a [BR-DEX-02].
[BR-DEX-02] Der Wert von "Invoice line net amount" (BT-131) einer "INVOICE LINE" (BG-25) oder einer "SUB INVOICE LINE" (BG-DEX-01) soll der Summe der "Invoice line net amount" (BT-131) der direkt darunterliegenden "SUB INVOICE LINE" (BG-DEX-01) entsprechen.
Example for a SubInvoiceLine:
<cac:SubInvoiceLine>
<cbc:ID>01.01.0020</cbc:ID>
<cbc:InvoicedQuantity unitCode="C62">0</cbc:InvoicedQuantity>
<cbc:LineExtensionAmount currencyID="EUR">0</cbc:LineExtensionAmount>
<cac:Item>
<cbc:Name>Pos01010020</cbc:Name>
<cac:ClassifiedTaxCategory>
<cbc:ID>S</cbc:ID>
<cbc:Percent>19</cbc:Percent>
<cac:TaxScheme>
<cbc:ID>VAT</cbc:ID>
</cac:TaxScheme>
</cac:ClassifiedTaxCategory>
</cac:Item>
<cac:Price>
<cbc:PriceAmount currencyID="EUR">2</cbc:PriceAmount>
<cbc:BaseQuantity unitCode="C62">1</cbc:BaseQuantity>
</cac:Price>
</cac:SubInvoiceLine>
As far as I understand, the LineExtensionAmount (=0) should not affect other LineExtensionAmounts. Therefore, this warning shouldn't be triggered. There should rather be a warning that there must not be any SubInvoiceLine with LineExtensionAmount = 0.