RDS MariaDB size actual more than usage.

Hi Everyone, I have used RDS MariaDB with the option Autoscaling enable. I receive alarm feeble storage of more than 120GB. But actually, I did check size storage in Databases is 54GB with the command below:

SELECT table_schema "DB Name",
        ROUND(SUM(data_length + index_length) / 1024 / 1024 / 1024, 1) "DB Size in GB" 
FROM information_schema.tables 
GROUP BY table_schema; 

Please explain and help me resolve issues. Best regard.