Ultimate Special Offers relies on movement from the cart page to the checkout in order to properly apply discounts. When PayPal is used on the cart page, customers are bypassing the Shopify checkout, preventing discounts from applying properly.
Some additional checkout buttons can be disabled in your theme editor, but additional checkout buttons on the cart page need to be manually hidden in your theme. Reach out to our support team if you want assistance with this.
Customers will still be able to pay with PayPal when they reach the checkout page.