Two apologies: one is that another post will immediately follow on this same passage, but with an entirely different slant, so I thought it would be better to separate them in case they lead in entirely different directions.
The second is for the atrocious pun in the title. If I remember rightly, every one of JA's works that she published in her lifetime was in the three-volume format: S&S, P&P, MP and E. I believe this was because printed matter, being so expensive, was commonly shared. A three-volume format would enable Person A in a household to read volume I and then pass it on to Person B while they continued with Volume II. (It is for this reason that Sir John's sending the Dashwoods his newspaper every day (Ch.6) represents more than just a sop. They wouldn't have been able to afford a daily paper - at that time probably The Times.)
Question is: did authors write to this format, or was it decided more-or-less arbitrarily by the publisher, or even the printer? Ch.22 (the last chapter in Vol.I) ends on what can only be seen as a cliffhanger, and in Vol.II Ch.1 (our Ch.23) there is a huge change in tone and perspective. This seems to imply that JA moulded the structure of her novel to a three-volume format, although we'll have to see how the other volume split works out. I haven't been able to find any external evidence regarding this, so I've had to use such internal evidence as the book itself presents.