How can we map azure reservation with the retail price.

Question

Thank you in advance for attempting to solve this issue
My organization has multiple Azure tenants, underneath we have 100+ subscriptions. We make a lot of reservations to save costs. However, as an analyst, I am trying to build an automated report that can map reservations with the retail price and determine how much savings we made using the reservation. I am using the below APIs to map the cost.

• Retail Price public API: https://prices.azure.com/api/retail/prices?api-version=2023-01-01-preview&meterRegion='primary'
• Reservation Orders: GET https://management.azure.com/providers/Microsoft.Capacity/reservationOrders?api-version=2022-11-01
• Reservation Transactions: GET https://management.azure.com/providers/Microsoft.Billing/billingAccounts/123456/providers/Microsoft.Consumption/reservationTransactions?$filter=properties/eventDate+ge+2020-05-20+AND+properties/eventDate+le+2020-05-30&api-version=2024-08-01&useMarkupIfPartner=True&previewMarkupPercentage=15.5

I am using ReservationOrderId to join reservation orders and transactions.

To Join the retail price I could find armSKUName and armRegion. However, there are multiple options available for armSKUName and armRegion. That causes duplicates. What I could find in retail price is, MeterId, SKUId, and ProductId what makes it unique, however, I cannot get such details from reservation orders or transactions.

I am trying to understand if there is any API that can uniquely map to the retail price with the reservation. It would be a great help for me and the community if you have encountered the same and found a solution.