Jimmy’s right, but on the basis of my first-hand experience, you need to make sure that the wording of your Plan’s Special By-Law is prescriptive, particularly with regard to business days vs calendar days, payments received vs payments receipted, dishonoured payments, and how the 10% (max) discount is applied (e.g. quarterly in arrears in our case).
By the way, if your objective is to ensure that Proprietors’ Levy Contributions are made (at least) on time, again on the basis of my first-hand experience, the permitted 10% (max) discount is about as effective as an incentive as the permitted 10% interest on arrears is a penalty/deterrent to late payments; not!