2.1.591 Part 1 Section 18.3.1.5, cellSmartTag (Cell Smart Tag)

a.   The standard states that the values for the type attribute are defined by the XML Schema unsignedInt datatype.

Office requires that the value be between 0 and 32768 inclusive.

b.   The standard indicates that there can be more than one cellSmartTag for a cell.

Office assumes that each cellSmartTag must have its corresponding type present in the smartTagType element in the smartTagTypes collection of the workbook.