Answer
Check whether the Data Source's column section defines an aggregate COUNT column directly, rather than a plain identifying column — for a Counter element specifically, don't create the count in the Data Source itself; instead select a plain identifying column (like an order number) in the Data Source's column section, so its own preview lists individual matching records rather than one pre-aggregated count row. Then configure the Lobby Element itself as the Counter type, pointing it at that plain column. Built this way, the drill-down correctly carries through the underlying filtered record set from the Data Source, rather than drilling into an unfiltered view of every record in the underlying table.