VAT rate and amount is not shown for non vatable items in OrderPrinter

I am modifying a receipt template in Order Printer.

My store has tax included in prices but some of our products are zero vat, so not taxable.

When I have a mixed order of vatable and non-vatable items, only the vatable items show a rate and amount, the rest others are blank -

How can I get to show that items are zero based tax ?

I have tried the following as a simple test.

{% for line_item in line_items %}

{{ line_item.title }} {% if line_item.taxable==true %} YES {% else %} NO {% endif %} {% endfor %}