2.1.1480 Part 1 Section 21.2.2.82, holeSize (Hole Size)

a.   The standard states that the val attribute specifies that the contents of this attribute will contain a hole size between 10 and 90.

In Office, the val attribute specifies that the contents of this attribute will contain a hole size as defined by the ST_HoleSize simple type.

b.   The standard implies that the val attribute is optional.

Office requires this attribute.