Questions about the authorship of Number One Ladies’ Detective Agency

So a number of years ago I read the first couple of books during a protracted stay in hospital with a nasty bout of pneumonia. Absolutely loved them, they were so pure and gentle and made me immediately want to live in Botswana.

Thought to re read it a few months ago and discovered the series has become quite lengthy, with 24 books! So I've been slowly borrowing and reading them.

My question is this: is there any possibility there are multiple authors using the McCall Smith name?

I've encountered a huge number of continuity issues.

These are just a few

>! Precious' baby lives for five days in one book, a few hours in another !<

>! the foster children's ages seem both to vary and not increase !<

>! Phuti Rataphuti's personality seems to shift back and forth from weak and naive to smart and independent !<

>! In one book the Rataphutis have two dogs, two books later they have zero dogs, don't like them and don't want one !<

>! One book dedicates an entire sub plot line to Mma Makutski's misadventure in buying a heart shaped bed for her upcoming wedding. The next book has a throw away mention about how the Mataphutis have to go search for a bed because they are building their own house and don't have any of their own furniture to put in it !<

>! Mr J L B Matekoni and Mma Romotswe are 'marrried for years and years' but based on the extrapolation from the book the relationship is no more than 3 years old !<

It occurs to me the first few books were Smith's, and the rest have been ghost written to meet contractual obligations.

it also occurs to me these are meant to be enjoyed as stand alone fluff and I'm taking everything too seriously lol