What is a reference margin and how do I use it correctly? When you set a reference margin rule, Paladin Point of Sale can automatically maintain a margin between a fluctuating cost and a retail price. Many stores want all retail prices to stay consistent—to end in .99 or. 95, for example. To do that, you can implement a rounding scheme to allow the reference margin to set a price that is rounded up to the nearest number that is consistent with your retail pricing. In this webinar, we simplify the process for you to follow.