It would be nice, if the standard procedure to calculate the count of the rows would be

rowcount:= DataSet.RecordCount;

instead of

rowcount := DataSet.MoveBy($FFFFFFFF);

If I place a new DBAdvGrid to a form in Delphi XE7 and forget to implement the OnGetRecordCount-Event when working with the FireDAC MySQL Tables, the Application just hang around for over 15 minutes.
If there is any good reason to hold this way of calculating the recordcount, please add a property like "DefaultRecordCountMethod" [rcmRecordCount, rcmMoveBy]
I would prefer to set rcmRecordCount to the default method.

Using dataset.RecordCount is not a reliable way to get the number of records for any type of dataset, so we cannot use that technique in TDBAdvGrid.
If you use a dataset with a reliable RecordCount implementation, I'd suggest to return that value from the DBAdvGrid.OnGetRecordCount event.

See many issue reports on RecordCount, for example:

This feature will not be implemented.