Odoo 15: Datev Export create two lines for product after import in datev

[mthiermann]

datev_export_xml Odoo V15

If I make an xml export of the outgoing invoices and import them into Datev, there are two lines per product in Datev.
When I look at the xml file, I see that there are really two "lines" (tags) with the same product or invoice line , but with a small difference. Only the first contains "net_product_price="19.950" ".
Presumably one is the invoice line and the other is the posting line.
Does it have to be like this? Our tax office clearly says no.

Is this perhaps just an Odoo or a setting in the module?

<invoice_item_list
product_id="POR123"
description_short="[POR123] Seifenschale ETHNO"
net_product_price="19.950"
order_unit="Einheiten"
quantity="6.00">
<price_line_amount
currency="EUR"
gross_price_line_amount="23.74"
net_price_line_amount="19.95"
tax="19.00"/>
<accounting_info
account_no="4440"
cost_category_id=""
booking_text="[POR123] Seifenschale ETHNO"
bu_code="13"/>
</invoice_item_list>

<invoice_item_list
product_id="POR123"
description_short="[POR123] Seifenschale ETHNO"
order_unit="Einheiten"
quantity="6.00">
<price_line_amount
currency="EUR"
gross_price_line_amount="23.74"
net_price_line_amount="19.95"
tax="19.00"/>
<accounting_info
account_no="4440"
cost_category_id=""
booking_text="[POR123] Seifenschale ETHNO"
bu_code="13"/>
</invoice_item_list>

Regards
Mario