I would want it to look like this:

If I try and set the "Cost" to "N/A" in the shipping extension, it still shows "$0.00" as the cost of shipping on the checkout page. Since we will be charging shipping costs in the final invoice that we create with our other accounting software, I do not want to mislead our client into thinking that shipping is "$0.00". I want it to say "N/A".
Can I adjust the "Cost" parameter to have a text variable instead of a number (i.e. "N/A" instead "0")? I see where I can do this in the database to already placed orders:

How can I make it so that the checkout screen shows "N/A" instead of "$0.00"?
Thanks in advance. I'm totally new to OpenCart and am still trying to wrap my head around it all.