188.8.131.52 Multivalue Property Value Instances
When working with multivalue columns in the context of table operations, clients set the 0x2000 (MultivalueInstance, %x00.20) flag bit in the column's PropertyType field to indicate that the multivalue column is to be treated as individual values. The MultivalueInstance flag MUST NOT be set for any column that does not also set the 0x1000 (Multivalue) bit in its property type. All PtypMultiple types in the table in section 2.11.1 set the 0x1000 bit.
The MultivalueInstance flag specifies that table operations are to treat multivalue columns as if they were multiple instances of a single-value column (as specified in [MS-OXCTABL] section 184.108.40.206.1).