Hi David,
Sorry for the delayed response.
If you want show the total summary value in SummaryRow then please try using Sum in summary format to display the summary total. We will update you the Vector summary type example as soon, mean while please refer the sample for show the summaries in GridGroupingControl.
Refer the sample form below link:
http://files.syncfusion.com/support/samples/Grid.Windows/7.3.0.20/Forums/GGCSummary.zipPlease let me know if you have any concerns.
Regards,
Lingaraj S.