What is a SppDiscounts in AWS CUR?

It appears there may be some confusion regarding the "SppDiscount" line item in your AWS Cost and Usage Report (CUR). Let me clarify:

The "SppDiscount" line item type does not actually refer to Savings Plan Purchase Discounts. Instead, it's related to a different type of discount program.

Savings Plans discounts are typically represented in the CUR by line items with types "SavingsPlanCoveredUsage" and "SavingsPlanNegation" as you correctly mentioned. These line items are associated with compute services like EC2, Lambda, and Fargate.

The "SppDiscount" you're seeing is likely related to a Private Pricing Agreement (PPA) or Enterprise Discount Program (EDP). These are customized pricing arrangements that AWS offers to some enterprise customers, which can apply discounts across a wider range of AWS services, including EC2, EKS, ECS, CloudWatch, and RDS, as you've observed.

It's important to note that PPA/EDP discounts and Savings Plans discounts are applied differently:

1. Savings Plan discounts are applied first to eligible usage.
2. After Savings Plan discounts are applied, any applicable PPA/EDP discounts (which would appear as "SppDiscount" in the CUR) are then applied to the remaining amount.

This sequential application of discounts means you benefit from both, but they don't stack additively. The PPA/EDP discount is applied to the already reduced rate from the Savings Plan, not to the original on-demand price.

If you're seeing "SppDiscount" line items without corresponding Savings Plan line items, it likely means you have a PPA/EDP in place, but may not have active Savings Plans, or the usage in question isn't eligible for Savings Plan discounts.

You may also review if the usage is related to the AWS Solution Provider Program as this may apply to you.

For the most accurate interpretation of your specific CUR data and discount applications, it's advisable to consult with your AWS billing & account team via our Support Center.

Sources
Savings Plan + PPA | AWS re:Post
Compute Savings Plan | AWS re:Post