Default AR Discount Class

If Use Classes is "Required" then you will also be required to enter an Default AR Discount Class.  The Default AR Discount Class will be used to populate the class field for discount transactions generated in Enter Customer Payments.

If Validate Classes By Account in Company Setup is checked, the list of valid classes will be limited by the entries defined for the  Default AR Discount Class in the Account Class Validation screen OR to all active classes, depending upon the Account Class Validation Type in Company Setup.