As mentioned in The Chart Data Model topic, the values data grouping are static. This means that unlike Category and Series Data Groupings they do not have associated filters, sorting and grouping expressions. In Nevron Chart for SharePoint each values data grouping is typically used to represent a single or multiple chart series (depending on whether there are any series data groupings). Because of that values data groupings contain properties, which are applied to the chart series generated for it.
Values data groupings are added, removed and edited by the Pivot > Data Groupings > Values tab page:
The properties of each values data grouping tab are explained in detail, by the following topics: