Все, разобрался, если кому надо модификатор:
<?xml version="1.0" encoding="utf-8"?>
<modification>
<name>loan_price</name>
<code>loan_price</code>
<version>1.0</version>
<author>Tom</author>
<link>loan_price</link>
<file path="catalog/controller/product/product.php">
<operation>
<search><![CDATA[$data['description'] = html_entity_decode($product_info['description'], ENT_QUOTES, 'UTF-8');]]></search>
<add position="after"><![CDATA[
$data['loan_price'] = $this->currency->format($product_info['price'] / 12, $this->session->data['currency']);
]]></add>
</operation>
</file>
<file path="catalog/controller/product/{category,product,search,manufacturer,special}.php">
<operation>
<search><![CDATA[if ($this->config->get('config_tax')) {]]></search>
<add position="before"><![CDATA[
$data['loan_price'] = $this->currency->format($product_info['price'] / 100 * 96.5, $this->session->data['currency']);
]]></add>
</operation>
<operation>
<search><![CDATA[$data['products'][] = array(]]></search>
<add position="after"><![CDATA[
'loan_price' => $data['loan_price'],
]]></add>
</operation>
</file>
<file path="catalog/view/theme/*/template/product/product.twig">
<operation>
<search><![CDATA[{% if price %}]]></search>
<add position="before"><![CDATA[<div class="card__credit"> Рассрочка от <a href="/installment/" target="_blank" class="card__credit--price">{{ loan_price }}</a></div>]]></add>
</operation>
</file>
<file path="catalog/view/theme/*/template/product/{category,product,search,manufacturer_info,special}.twig">
<operation>
<search><![CDATA[{% if product.price %}]]></search>
<add position="before"><![CDATA[
<div class="product-card__price">
<span class="product-card__price--actual-wrp">от <span class="product-card__price--actual">{{ product.loan_price }}</span></span>
</div>
]]></add>
</operation>
</file>
</modification>
