Modify S fields
The S-Field contains four values: the minimum, the low percentile, the high percentile, the maximum value.
See XSField Class to find an example on how to set the Low Percentile and the High Percentile to respectively 25 % and 75 % of the range covered by the Min-Max values.
So that if Min = 100 and Max = 200, LowPercentile = 125 and HighPercentile = 175.