A relationship between two compositions discussed recently

I was looking over some recent blog articles and I noticed a slight similarity between these two compositions.

5184 Pudsey Surprise Major
Edwin A Barnett (rotated)

23456  B  M  W  H
-----------------
54632     –  –  3
26354  3
53462     –  –  3
-----------------
3 part.

 

1280 Yorkshire Surprise Major

J Eric Brosius

23456   B  M  W
---------------
54632      -  -
24536      2
65324   3
23456      -  -
---------------

The similarity is the "M W 3B M W". The three homes in the Barnett composition can obviously be ignored, but what about the extra two middles in the Brosius composition? Somehow the two middles must be equivalent to the other two parts of the Barnett composition.

Write out the middles, wrongs and befores like this:

23456  B  M  W
--------------
64523  3
25346     -  -
43652     -  -
--------------

The coursing order at the end of this block is 53462, the same as calling a middle from the plain course. Calling two more middles returns to the plain course, and that's the Brosius composition (rotated). Calling the whole block three times, with the addition of blocks of three homes, is the Barnett composition.