2.1.1584 Part 1 Section 21.2.3.14, ST_ErrValType (Error Value Type)

a.   The standard states that the enumeration value stdDev specifies that the length of the error bars shall be Error Bar Value standard deviations of the data.

In Office, the enumeration valuestdDev specifies that the length of the error bars shall be the standard deviation for each data point and then multiplied by the val (Error Bar Value).