I am unable to pass formatted Values to the <value> option in Data Labels.  See attached Data Grouping format syntax and Pie Chart.

Hello Steve,
Currently you can't use formatting on the Value field. You should pass the format expression in the Label field and use <label> for your Data Label -> Format field.

With the next service pack of the Vision for SharePoint we will allow formatting of the Value through the Data Label Format Strings.

Best Regards,
Nevron Support Team

Great tip!  Works well.