Hi Mark,
The following code snippet shows how to get rid of the automatic ordinal scale content inflate:
NStandardScaleConfigurator scaleX = (chart.Axis(StandardAxis.PrimaryX).ScaleConfigurator as NStandardScaleConfigurator);
scaleX.InflateContentRange = false;
NStandardScaleConfigurator scaleDepth = (chart.Axis(StandardAxis.Depth).ScaleConfigurator as NStandardScaleConfigurator);
scaleDepth.InflateContentRange = false;
Hope this helps - let us know if you meet any problems.