Discounts and / or Loyalty Points can also be pre-set for different customers by using Price Levels.
Price Levels can be set up and edited in Items / Price Levels
Price Levels can be allocated to customers in Contacts under the Sales tab.
A Price Level can have different discounts / surcharges for different stock categories or items. For example you could have price levels for: VIP Customer, Trade 1, Trade 2, Distributor and Staff.
See Price Levels