line item error

I have multiple discounts per quantity ordered. I want the "Line Item Name" in the payment field to show what % discount is applied. I have been working with a code but can't seem to get it work, keep on getting errors. This is the code I've been working with:

=(if Discount > 18 then "30% Bulk Discount” else if Discount > 12 then “20% Bulk Discount” else if Discount > 6 then “10% Bulk Discount” else "")