2.1.169 Part 1 Section 17.4.71, tcW (Preferred Table Cell Width)
a. The standard states that if the w attribute is 0, then preferred cell width is 0.
In Word, if the w attribute is 0, then the type attribute is interpreted as auto.
b. The standard does not specify the behavior when type is nil.
Word interprets the type attribute value as auto when the type attribute has a value of nil.