In some cases Azure: SQL Database Cost/Usage reports categorized by Service Tier may report a significant amount of cost/usage under the 'Other' Service Tier. 

https://apps.cloudhealthtech.com/olap_reports/azure_usage/sql_database

'Other' is a catch-all Service Tier for when CloudHealth cannot determine the Service Tier based on the data available from the Azure API collection.

This can often occur when an SQL Database that commonly runs under an Elasticpool is temporarily moved out of the pool.