Thank you.
I found the file: admin/controller/responses/sale/invoice.php
I made the following changes between lines 141 & 151: commenting out 'price', 'total' & $total_data lines
And with your language change, I now have a Packing Slip with no prices!
$product_data[] = array(
'name' => $product['name'],
'model' => $product['model'],
'option' => $option_data,
'quantity' => $product['quantity'],
//'price' => $this->currency->format($product['price'], $order_info['currency'], $order_info['value']),
//'total' => $this->currency->format_total($product['price'], $product['quantity'], $order_info['currency'], $order_info['value']),
);
}
//$total_data = $this->model_sale_order->getOrderTotals($order_id);