Once again, thank you for your help.
The change worked out well. However, there appears to be a side effect. I tested the cart by modifying the quantity of an item that requires shipping. When I manually modified the quantity in the cart to reflect 2 items, I proceeded to click on the 'update' button and the shipping charges disappeared.
I tested the cart again by going back to my e-commerce site and proceeded to add the same item to cart by using the add to cart button. The results were the same.
You can visit my site at hrproducts.php to test what I am seeing.