Hello Paul,

There are different approaches to solve this task. Maybe you could use ExternalSummary to convert your minutes into Hours + minutes. For example:

private void ultraGrid1_SummaryValueChanged(object sender, Infragistics.Win.UltraWinGrid.SummaryValueChangedEventArgs e)
{
    double number;
    if (e.SummaryValue.SummarySettings.SourceColumn.Key == "Duration" && Double.TryParse(e.SummaryValue.Value.ToString(), out number))
    {
        TimeSpan span = System.TimeSpan.FromMinutes(Convert.ToDouble(e.SummaryValue.Value));
        string hours = ((int)span.TotalHours).ToString();
        string minutes = span.Minutes.ToString();
        eArgs.SummaryValue.SetExternalSummaryValue(hours + " h " + minutes + " min");
    }
}

private void ultraGrid1_ExternalSummaryValueRequested(object sender, Infragistics.Win.UltraWinGrid.ExternalSummaryValueEventArgs e)
{
    eArgs = e;
}

Please take a look at the attached smaple and video file for more details and let me know if you have any questions

Regards