You have to have 5 items in a subscribe and save delivery to get the maximum discount listed on each of the items.
If you put your 25% item into a delivery next month and also subscribe to 4 other items in the same monthly delivery that show “up to 10%” discount, you’ll get 25% off the first item and 10% off the other 4.
Remove one item so you only have 4 items in the delivery and you’ll probably (I’m simplifying) get the lowest mentioned discount on each item rather than the highest - e.g. 5% instead of 25%.