getInvoiceAmountNet example

            if ($order->getNet()) {
                $invoiceAmountNet += $this->rounding->round($price, $taxValue, $detail->getQuantity());
            } else {
                $invoiceAmountNet += round(($price * $detail->getQuantity()) / (100 + $taxValue) * 100, 2);
            }
        }

        if ($order->getTaxFree()) {
            $order->setInvoiceAmountNet($invoiceAmount + $order->getInvoiceShippingNet());
            $order->setInvoiceAmount($order->getInvoiceAmountNet());
        } elseif ($order->getNet()) {
            $order->setInvoiceAmountNet($invoiceAmount + $order->getInvoiceShippingNet());
            $order->setInvoiceAmount($invoiceAmountNet + $order->getInvoiceShipping());
        } else {
            $order->setInvoiceAmount($invoiceAmount + $order->getInvoiceShipping());
            $order->setInvoiceAmountNet($invoiceAmountNet + $order->getInvoiceShippingNet());
        }
    }
}