Puzzles about inserting Visio diagram

Hi guys,

I have a puzzle about difference between the size of visio figure and actual visio diagram. like below:

the size of visio figure in DOCX are width:841.75pt and height:118.55pt. but the actual size of my visio diagram is width:1626.75pt and heitht:204pt.

Can anyone help to figure out how to calculate the size of visio figure in DOCX from actual visio diagram?