[ms-xlsx]: Excel (. xlsx) Extensions to the Office Open xml spreadsheetml file Format

flattenHierarchies: A Boolean ([XMLSCHEMA2] section 3.2.2) attribute that specifies whether to display members from different levels of the same PivotTable ([ISO/IEC29500-1:2011] section 18.10) cache hierarchy of this PivotTable ([ISO/IEC29500-1:2011] section 18.10) named set in the same PivotTable ([ISO/IEC29500-1:2011] section 18.10) field (1). MUST be "false" if ignore is "true". If a CT_CalculatedMember element that corresponds to the PivotTable ([ISO/IEC29500-1:2011] section 18.10) named set exists, this attribute MUST be equal to the flattenHierarchies attribute of the CT_CalculatedMember element.

ignore	flattenHierarchies	Meaning
"true"	"false"	The ancestor cacheHierarchy element of type CT_CacheHierarchy ([ISO/IEC29500-4:2011] section A.2) of this PivotTable ([ISO/IEC29500-1:2011] section 18.10) named set is discarded.
"false"	"false"	Each member from a different level of the same PivotTable ([ISO/IEC29500-1:2011] section 18.10) cache hierarchy of this PivotTable ([ISO/IEC29500-1:2011] section 18.10) named set is displayed in a separate PivotTable ([ISO/IEC29500-1:2011] section 18.10) field (1).
"false"	"true"	All members from different levels of the same PivotTable ([ISO/IEC29500-1:2011] section 18.10) cache hierarchy of this PivotTable ([ISO/IEC29500-1:2011] section 18.10) named set are displayed in the same PivotTable ([ISO/IEC29500-1:2011] section 18.10) field (1).