Thanks to Ellen Moody's chronology (in the P&P FAQ), I have just built a time chart of the novel, putting in relation the number of pages and the time which goes by (I would like to scan that chart and put a link to it, but I do not know how to do it).

Of course we have to wait for 2 weeks more and the end of the novel to see whether there is time symetry in the construction of the novel.

So far I can only draw a few observations relating to Part1 and Part 2.

Part 1 (ch 1 to 24) lasts 1,5 month and in my edition it takes up 112 pages, exactly 1/3 of the novel.
Yet very few really significant events occur apart from Mr Collin's proposal.
It is as if JA took her time to set the scenes so that the reader may have an accurate vision of every character before the plot really unfolds. Apart from Lady C (who is mentioned by Wickham) and Georgiana (mentioned by Caroline B) all the characters have been presented to us, and seen to act according to their characters.