2.1.1508 Part 4 Section 22.214.171.124, line3DChart (3D Line Charts)
a. The standard states that the values of the child element axId are defined by the XML Schema unsignedInt datatype.
In Office, child element axId has a maximum value of 2147483647.
b. The standard states that the maxOccurs value for the ser child element is unbounded.
Office limits the occurrences of this element to 255.