If my customers have a default discount on their price list, can they use a promo code on top of it?

Yes. Since the promo code is a one-off discount to entice your customers to purchase, we will allow them to apply the promo code discount as well.

Therefore, if your customer already has a discount applied to their price list (aka contract pricing), the promo code discount will be added on as a successive discount. Click here to understand how QuickBooks Commerce calculates successive discounts in such instances.