No, the Quantity Breaks app applies the discounted pricing in the cart before the customer proceeds through the checkout process.
Whatever price is in the cart is the same price used for shipping.
The Quantity Breaks (standalone) app is no longer available for new installations. If you are currently using Quantity Breaks, you will be able to continue using the app on a grandfathered plan.
New requests for Quantity Breaks will be directed to Custom Pricing which has a Quantity Breaks plan available. For more information, please visit Custom Pricing Overview.
If you'd like move from Quantity Breaks (standalone) to Custom Pricing, please visit Switch from Quantity Breaks to Custom Pricing.