Hello Ivan Zeljkovic,
Welcome to the MS Q&A Forum.
I assume you are using the Azure Consumption Reservation Recommendation API command.
Reservation purchase recommendations are calculated by analyzing your hourly usage data of Virtual Machine Resources over last 7, 30, and 60 days. Azure calculates what your costs would have been if you had a reservation and compares it with your actual pay-as-you-go costs incurred over the time duration in overall based on your organization's usage (including past data).
You could also review Recommendations in the Azure portal on Purchase reservations blade or in Azure Advisor.
If you would like to get the list of VMs which are using the specific VM size at this specific moment, you can simply use Azure Portal VMs blade and filter by the size parameter
Reference:
- Reservation recommendations
- Understand Azure reservation usage for your individual subscription with pay-as-you-go rates subscription
Hope above answers your question and concern. Let me know if you need additional assistance. If the answer was helpful, please accept it and complete the quality survey so that others can find a solution.
Sincerely,
Olga Os.