2.1.1619 Part 4 Section 18.104.22.168, wMode (Width Mode)
a. The standard states the val attribute specifies the layout mode for the width.
In Office, the val attribute specifies the layout mode for the parent element.
b. The standard states that edge is a valid value of the val attribute for wMode.
Office only saves a val of factor. Files opened with val equal to edge will be changed to factor on save and the val of sibling element w will be updated to reflect this mode change and correctly preserve the manual size.