If the Data Product is a “Variable Product”, then the amount saved in the frontend is calculated, an example like: You save 10$ (20%)
Meanwhile, if the Data Product is changed to “Subscription Variable” on the same product and price, then the saving amount is not calculated, it only says You save 0$ (0%)
Reminder: The “Subscription Variable” data product only appears when you install and activate the WooCommerce Subscriptions plugin.