2 Cent Documentary Plate Varieties: More Guide Dot Examples

There have been multiple examples of the so-called guide dots at the top centers of the battleship stamps in recent posts.  In this post are examples of two stamps with dots at the bottom of the stamp.  In the first example their is a dot in spandle toward the top of the stamp, but there is also a dot at the bottom just inside the frame line at center.

The example below includes a dot at bottom center outside the design of the stamp.

No matter what I read, I can't figure how the positioning of these dots made for accurate centering of the transfer roll on the plate.