It is said that great three point sermons have seven points:
I blame St Paul who often managed more than one 'finally brothers' and sometimes put 'finally' at about the half-way point of his letters.
I have heard preachers in the past who have written out their material carefully but feel they haven't been complete enough and try and add more after their script has finished. They are like sermons with no brakes. Once you go off-script the only way to stop is to drive the thing into a tree. The sudden halt. Tony Blair did it with his last Prime Minister's Question Time. After all his House of Commons erudition he finished with, 'That's it; the end.'
So a recent, excellent sermon I heard had 'finally' at about the 75% mark, followed by a new point. Then we heard the expression '...my last two points' followed by the promise of a 'final slide.' This was immediately followed by 'Before I put up the final slide' and a brief comment, then a slide with four questions on it.
A useful preparation point for public speakers is that the last thing you intend to say should be the first thing you write. It will summarise your whole talk and therefore you need to know what it is going to be before you start. The first thing you say should be a brief link from what has happened so far. Your first sentence should be written, if only in your head, in the five minutes before you speak.