The Collection with Offer which is displayed on Top in “List of Offers” will be applied. Then the next Collection Offer that is in the list will be applied.
Example: Silk Summer Top is in collection “New Collection” (Buy 2 for 5% Off) and “Clearance Sale” Collection (Buy 2 for 10% Off).
If “New Collection” is displayed first in “Offer List” then Silk Summer Top will display (Buy 2 for 5% Off) on the product page.
You can simply drag and drop “Clearance sale” on Top of the offer list and (Buy 2 for 10% Off) will be displayed on the Product page.