In short, we don't guarantee that data in your Data Warehouse Shares will be aggregated to give you exactly one row per set of dimension values.

As these are Data Warehouse Shares we expect the end destination of the data to be a database of some kind, and that the database has the ability to aggregate data.

Data in Data Warehouse Shares should be treated as raw data. Depending on the dimensions in your Share, the data may be aggregated to some degree but this is done for internal optimization purposes and is not a guarantee of row uniqueness.