Setting the AutoRescaling property to true enables the auto-adjustment of the scale's bounds depending on the current value.
The scale's ArcScale.MinValue is automatically reduced when the scale's current Value falls into the range [MinValue; MinValue+ThresholdMin]. Similarly, the scale's ArcScale.MaxValue is automatically increased when the scale's current Value falls into the range [MaxValue-ThresholdMax; MaxValue]. So, the scale's bounds are automatically expanded when the scale's Value reaches one of the bounds.
The ThresholdMin and ThresholdMax are marked for a circular gauge in the image below: