If discounts are used on invoices and/or payments (as set up in AR Company Parameters), the discount will default based on the payments terms set up in HQ Payment Terms and assigned to the customer, contract, or material quote.
If you are using Material Sales, discounts may be based on materials rather than on the invoice line total. If based on materials (i.e. the Discount Based on Material option is checked in HQ Payment Terms), the discount may be calculated as a percent of the material or based on an amount per material units, such as $1.00 per ton sold. Discount rates/amounts can default from MS Quotes (if the material exists on a quote for the customer, job, or inventory location), AR Customers, or HQ Materials (using the payment discount type and a specified rate/amount).