You can specify the alignment for a multilayered seam which is assigned to an internal line or edge.
To align a multilayered seam:
On the Main toolbar, click Select.
On the Horizontal contextual menu:
To edit a seam on an edge, ensure Pieces is selected.
To edit a seam on an internal line, ensure Internal is selected.
In the 2D window, click the edge or internal line to select it.You can also select the edge or internal line in the 3D window.
Go to the Context view, in the Materials section.
Click the Seam Alignment you want.
By default, when assigning multilayered seams, center alignment is set.