Insert of words, lines, paragraphs.

[Wladimir D]

It seems that there is a sixth case of the top-line addition.
Why write the first line (highlighted in yellow) to interrupt, not to touch the outline of the circle, if in a bottom of the page enough space?  Initially the author has written this paragraph, and then began to fill the text of the inner circles. He did not know what will be in point of interruption?
Have numerous cases of inserting characters inside of words, which are different in thickness by rest of the letters. See sample. Because of what it is going on? I have two explanations.
1. Author doubted the spelling and leave gaps. Then, finished writing symbols.
2. It is possible that copying (drafting) of the text was carried out stepwise, simultaneously on multiple lines. See f103v.
        A third explanation offered to Sergei Averyanov. The author in the process of writing do calculations (encoding) the same pen on  extraneous sheet , and when returning to the text had to dip nib in the ink.