'weight' => $this->weight->format(($product_info['weight'] + $option_weight) * $product['quantity'], $product_info['weight_class_id'], $this->language->get('decimal_point'), $this->language->get('thousand_point'))
'weight' => $this->weight->format(($product_info['weight'] + (float)$option_weight) * $product['quantity'], $product_info['weight_class_id'], $this->language->get('decimal_point'), $this->language->get('thousand_point'))