Hi again,  wmldwilly.

Our engineers have been constantly adding new features and improving the ones you already have. 

You're also right. The Discount item is specifically designed to deduct from the total amount.  The steps you've been doing is also correct. Although, you need to make sure to enter a negative amount. 

I'll also share your additional feedback about adding a discount column with our engineers. They'll be able to take a look at this and check if they can add it in the upcoming updates.

Visit us again anytime you have other questions.