Punctuation!

Hostage to Fortune is now in its final stages before publication.
The copy edit came back with some well spotted errors marked (A company called FP became FM for some reason best known to my fingers and Berry Head (near Dartmouth) became Barry Head – I blame my fingers for that one too!). The most frequent changes/corrections were in punctuation. I wonder if this is what other writers find.
I have learned, in the ten years I have been writing and publishing my books, that speech ends with a comma if the following text indicates ‘XXX said’ or ‘XXX replied’ but with a full stop if the speech stands as its own paragraph or if the text that follows is, indeed, a new sentence. This is something I now try to do to save the copy editor (or the editor’s software) an incredibly large number of changes.
Another change that seems to have occurred in those ten years is the proliferation in the use of the semicolon.
When I was at school, admittedly over fifty years ago, this item of punctuation was frowned upon. My English teacher taught that, if a comma did not serve, the second clause should form a new sentence. Perhaps that was her personal preference rather than the prescribed wisdom of the day.
Looking at Wikipedia, that fount of all knowledge, the use of the semicolon in English texts since 1500 showed remarkable swings in popularity for the first 150 years, reaching a peak in the 1660s before declining sharply. Recovery through the Eighteenth century saw another peak being reached in the early 1800s before a steady and continuous decline through that century and the last, reaching a low point not seen since the 1650s in 2001.
Since then the trend has been reversed.
My (completely unscientifically researched) theory is that this is the influence of the Americans and American software designers – particularly in Microsoft – where Word seems to frequently indicate a grammatical error when a comma is used mid-sentence.
And don’t get me on split infinitives!
Or the use of the exclamation mark (point?)!
Or whether a question mark should be used after rhetorical questions?
Or when dashes are acceptable – or not.
Anyway, I do hope that people who read Hostage to Fortune (and my other books, of course) will find the story(ies) so gripping that they do not notice the punctuation at all!