Folio reorder in the herbal section

[ahalay-mahalay]

So folks, this may be interesting, but most likely it is nothing...
I arranged those pages the following way. Quires 1, 2 and 3 stay the same (30 pages)
Then go Quire W(25,27,28,29,30,32), Quire X(35,36,37,38), Quire Y(49,42,44,45,47,56), Quire Z(51,52,53,54), those are just random placements that preserve the connected folios.
That gives 41801 words of a continuous Herbal-A text across 86 pages.
Then I built a Spearman matrix of the page-to-page similarity based on the most frequent bi-grams.

   

So this one is interesting since it has the noticeable (and very regular) grid. The light gray noise pattern is the similarity between pages in range of 0.4-0.6 of the Spearman correlation coefficient.
The three dark lines for folios f14v, f27v, You are not allowed to view links. Register or Login to view. represent pages that are very different from the rest at 0.19.

Has anyone noticed anything like that before or is that one of those dull things that has already been reported a decade ago?