2.1.447 Part 1 Section 17.15.2.40, sz (Nested Frameset Size)

a.   The standard allows any string for the val attribute.

For the val attribute, Word allows an integer between 1 and 32,767 followed by *; an integer between 1 and 500 followed by %; or an integer which divided by pixelsPerInch gives a value between 0 and 22.

b.   The standard states that no information shall be implied about the size of the current frameset when this element is omitted.

Word implies that the size of the current frameset shall be a relative measurement with a value of 1 when the sz element is omitted.