If a product already has a discount, and is then added to a discount group, will the new discount be applied on top of the existing discount, or will it override the existing discount?
Bold Discounts applies it's discounts to the price that appears in the price field in the Shopify admin product page. The original price will be moved to the "compare at price" field, and the new discount will be applied to the original price. If there is already a price in the "compare at price" field from a previous discount, the compare at price will remain unchanged.