If you are asking is it possible to add an unbound column and then place a summary on it the answer is yes.

Add the column and a summarysetting for the column in the InitializeLayout event.  Be sure to set the proper datatype the default is String.

Probably want to fill in the values in the IntiliazeRow event or if it's something derived from others columns add a WinCalcManager to the form and a formula to the unbound column.

Hope that helps,

Nick