I agree with your interpretation of the endgame, quisling but I had no trouble with the 3rd paragraph, in fact I found it quite helpful.
However, I had an exchange (at the other place, quite early on) with someone who also felt it was confusing. I used a specific example as an illustration, which I've subsequently edited out, but I'm sure you'll know what I was getting at.
Q - I don't understand the third paragraph. the preamble is poorly written, imho.
(Me) The 3rd paragraph explains why some clues are to be entered starting with an empty cell (**** becomes a longer answer later on, but its space within the grid starts inside one of the initially empty blocks - so it's a 5 letter space for a 4 letter word to begin with - in this way it maintains symmetry).
Q - But its symmetrical entry would be *****, which isn't in Chambers, or do I misunderstand you?
(Me) - ***** is a given name and is one of the new entries.
By the way, the name is in Chambers (fem of '****').