I'm trying to figure out discount items... we currently bill discounts as a negative "service for sale" item which... yeah. Anywho - I figured out how to do a basic % discount item, which will discount the immediately preceding line on a transaction. It seems like I can do a transaction discount, which would apply to the entire transaction, which would be AWESOME, but the "help center" is telling me to select a discount type when creating the item and... that is not an option for me lol

Another option is to add a subtotal line it will subtotal all preceding lines then add the discount line it will discount the subtotal

There are also promotions you could create, which could be auto or manually applied. In which you could provide a search which provides the list of items that need to be discounted. Or select even the customers eligible for that promotion.