If the ValueType is set to Custom, then you can use the CustomMinusFormula and CustomPlusFormula to specify the values of the error for each data point. Otherwise, the amount of error is determined by the Value property. If you change the ValueType of an error bar, the Value property will be set to the default value for the new error type. This value is 2 for a FixedValue error type, 5 for a Percentage error type, and 1 for a StandardDeviation error type. If you create a new error bar using ExcelWriter, it will have a default ValueType of FixedValue. |