Hi,
Now, I found the reason of "0.2646".

You can open the shape window and open Document Stencil,
and drag and drop the shape that has inserted text field from drawing to the document stencil.(Master.2)
Or you can copy the shape on the drawing and paste it to the document stencil.(Master.3)
Now, here are 2 masters.
I found 2 masters have different page size, page width and page hight.
You open the drawing window of the master, double clicking the master icon of Master.2.
If you move the master shape slightly, you can find the page of the master.
The size of the page is just the same as the master shape.
But the page size is larger than the master, if you open the Master.3. (Image25.jpg)
Page width and height are larger than the width of master shape by 0.5292 mm.
0.5292 mm = 0.2646 mm x 2
The Master.3 is on the center of the page larger than the master shape by 0.5292 mm.
Therefore the PinX = Width*0.5 + 0.2646.
It may be sure that the copied shape in the clipbord has the margin of 0.2646 mm around the shape.
