“Last Month” date range for Azure SQL Database Rightsizing report will includes all the months combined instead of the max of the particular month requested. If you would like to see individual months, your query can be adjusted.
As a work-a-round, select the specific date range in your query to see a more detailed set of results.
Here are the monthly metrics the platform has in the asset DB for this particular SQL query:
{"month"=>Sun},
{"month"=>Mon},
{"month"=>Tue},
{"month"=>Wed},
{"month"=>Thu},
{"month"=>Fri},
{"month"=>Sat},