Forum Discussion
Solved
Cost increases when selecting Amortised cost in cost analysis
Hi, this seems like a bug. When i select Amortized cost in Cost analysis, our monthly cost jumps from $25,664.54 to $76,315.83. The resource that causes the jump is a Reservation for a D4asv5 virtua...
This was a known issue and has now been resolved. If you require further information, including the root cause analysis (RCA), please contact Microsoft Support.
Seems it is an expected behavior tied to how reservations are accounted for, the jump reflects how Azure spreads reservation costs over time for reporting accuracy. It does not mean you are being overcharged but simply shows the true daily cost allocation of your prepaid reservation:
https://learn.microsoft.com/en-us/azure/cost-management-billing/reservations/view-amortized-costs
https://learn.microsoft.com/en-us/azure/cost-management-billing/reservations/reservation-utilization
https://learn.microsoft.com/en-us/azure/cost-management-billing/costs/quick-acm-cost-analysis