payment_company/shipping_company это другие поля, но спасибо, разобрался, сделал так:
$customer_info = $this->model_sale_customer->getAddress($result['address_id']);
$this->data['customers'][] = array(
'customer_id' => $result['customer_id'],
'name' => $result['name'],
'email' => $result['email'],
'company' => $customer_info['company'],
'customer_group' => $result['customer_group'],
'status' => ($result['status'] ? $this->language->get('text_enabled') : $this->language->get('text_disabled')),
'approved' => ($result['approved'] ? $this->language->get('text_yes') : $this->language->get('text_no')),
'ip' => $result['ip'],
'date_added' => date($this->language->get('date_format_short'), strtotime($result['date_added'])),
'selected' => isset($this->request->post['selected']) && in_array($result['customer_id'], $this->request->post['selected']),
'action' => $action
);