2.1.772 Part 1 Section 18.104.22.168, members (Members)
a. The standard does not state how to handle the absence of the level attribute.
Excel allows child member elements in this collection to be from all hierarchy levels under this circumstance.
b. The standard states that the values of the level attribute are defined by the XML Schema unsignedInt datatype.
Excel requires the value of this attribute, when present, to be more than 0 and less than the value of the count attribute of the associated PivotCache's cacheHierarchy element with the same index as the parent pivotHierarchy element, if that value is greater than 0.