Aggregation of rate elements with rate subelements Subscription billing

[tvc_em]

Dear Experts,

I need to achieve the following usage-baseds cenario in SAP Subscription billing and I'd need your input.

An external system will send to subscription billing usage records of rate elements "drivers" and "vehicle".
Both rate elements have the same 2 rate subelements: "active" and "inactive".

For the usage of 0 to 19 units (both "drivers" and "vehicle", both "active" and "inactive") a fixed amount is billed every month, ex. 50€.

From the 20th units on, a price per unit is billed in addition to the fixed price, ex. 5€/1ea. 
The same price is billed for "drivers" and "vehicle", "active" and "inactive".

How do you suggest to achieve this in a "simple" way?
I know I should use Tiered pricing, but this doesn't support Fix price type.
I also know that I need to set up an aggregation to have the rate elements with corresponding rate subelements contributing all together to the quantity included in the fixed amount: I set up an aggregation in the aggregation catalog and I added a step in the pricing tree of the price element specification (see screenshots) but the system doesn't aggregate the quantities coming from the usage records.

Any help would be much appreciated!

Thank you in advance
Elena

[Juan_Torrero]

This may be better handled by other LoB, Sales rather than Finance, since there are pricing elements involved.

[tvc_em]

Hello, 

all questions and blogs related to SAP subscription billing are posted in "Financial Management Q&A".
If you click on the link "Ask a question" in the homepage of the SAP help for Subscription billing, you land directly in "Financial Management Q&A".

Kr

[CarstenJ]

this is the right place for your question 😉