Happy St. Patricks Day!

Here's my question:  How can you remove "Client Discount" from the client invoice?

I've gone into Settings/Invoice Setup/Additional Charge Description and then tried to delete the item (Client Discount) but I receive a message that states:  "Cannot Delete Default Setup File"

I'd like to remove the description from my Default Invoice Setup and only include this item on invoices where I actual provide a discount.  Instead of this category/description being shown on every invoice.

Can anyone advise?

Much thanks!