The savings plans quotes the 1 year no upfront commitment option a higher effective discount when compared to other two offering types, the other two offering types are partial upfront and all upfront which should ideally have a higher discount when compared to no upfront offering type.
The cloud platform is able to cover more of the usage as the customer buy more discounted savings plans. The effective savings percentage is lower, however the coverage and actual savings are higher. This is because savings plans are applied to the instances with the deepest discount first. So actually as more saving plans are purchased, the average discount on those savings plans will decrease. Hence, in the 3 year purchase cards, the coverage is staying the same, which is why the effective discount is increasing.