Custom discount not showing on invoice

I have added a custom discount on order using below code and its working perfectly fine but when create invoice from admin then custom discount not showing.

File: app/code/Vendorname/Modulename/etc/sales.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Sales:etc/sales.xsd">
    <section name="quote">
        <group name="totals">
            <item name="prepaiddiscount" instance="VendornameModulenameModelQuoteAddressTotalPrepaidDiscount" sort_order="400"/>
        </group>
    </section>
</config>

then created the model
File: app/code/Vendorname/Modulename/Model/Quote/Address/Total/PrepaidDiscount.php

<?php
namespace VendornameModulenameModelQuoteAddressTotal;


class PrepaidDiscount extends MagentoQuoteModelQuoteAddressTotalAbstractTotal
{

    public function collect(
        MagentoQuoteModelQuote $quote,
        MagentoQuoteApiDataShippingAssignmentInterface $shippingAssignment,
        MagentoQuoteModelQuoteAddressTotal $total
    )
    {
        parent::collect($quote, $shippingAssignment, $total);
        
        $items = $shippingAssignment->getItems();
        if (!count($items)) {
            return $this;
        }
        $prepaidDiscount = 10;
        if($prepaidDiscount){
            $address             = $shippingAssignment->getShipping()->getAddress();
            $label               = 'Prepaid Discount';
            $discountAmount      = $prepaidDiscount;   
            $appliedCartDiscount = 0;
            if($total->getDiscountAmount()) {
                $appliedCartDiscount = $total->getDiscountAmount();
                $discountAmount      = $total->getDiscountAmount() + $discountAmount;
                $label               = $total->getDiscountDescription().', '.$label;
            }    
            
            $total->addTotalAmount($label, -$discountAmount);
            $total->addBaseTotalAmount($label, -$discountAmount);
            
            $total->setDiscountDescription($label);
            $total->setDiscountAmount(-$discountAmount);
            $total->setBaseDiscountAmount(-$discountAmount);

            $quote->setCustomDiscount(-$discountAmount);
            $quote->setSubtotal($quote->getSubtotal() - $discountAmount);
            $quote->setGrandTotal($quote->getGrandTotal() - $discountAmount);
            $quote->setBaseSubtotal($quote->getBaseSubtotal() - $discountAmount);
            $quote->setBaseGrandTotal($quote->getBaseGrandTotal() - $discountAmount);            
        }

        return $this;           
    }
}

But discount not showing while creating the invoice, Any idea what I am doing wrong??