Use Allow discounts to stack to choose how matching PD Discount Manager rules combine in WHMCS. Priority alone does not normally make a smaller offer beat a better one when stacking is off.

Compare the matching rules first

Open PD Discount Manager → Discounts and identify the rules that could match the same item. Check their product target, price scope, billing cycle, audience, dates and duration. A rule matching the setup fee can have a different effect from a rule matching recurring price.

In each rule, review Priority under When & limits. A lower number runs earlier where priority matters. Save only the change you intend, then check the list status.

Keep the best single offer

In Settings, leave Allow discounts to stack off for the single-rule choice. The evaluator compares the total saving across the item’s recurring and setup components and selects the best matching rule. Priority breaks a tie between equal savings; it is not a general override for an inferior saving.

Do not compare just the percentages if the rules apply to different components or have different fixed amounts. Review the actual eligible price and currency.

Combine offers deliberately

Turn stacking on only when combined offers are intended. Matching rules are applied in priority order to the remaining amount. For example, on a base price of 100, successive 10% and 25% rules leave 67.50 before other charges and rounding; they do not mean 35% off. Review configurable options and separate platform promotions in the actual checkout result.

A bundle-priced item is handled by its bundle rather than receiving an additional product-rule discount. A free-trial item also follows its trial path. Turning stacking on is not a promise that every kind of offer will combine.

Verify the customer result

Use a controlled test case with the intended product, cycle and audience, and compare the final invoice with Usage. Check both setup and recurring lines. Avoid changing a real client’s service or placing a live order merely to inspect the settings. If the amount remains unclear, compare the matching rules, priorities and expected calculation with the actual invoice lines.

See the PD Discount Manager WHMCS guide for related tasks, or explore PD Discount Manager.