Interesting to see the variety of responses in this thread....

The reason I was asking is that I've noticed that sometimes the mix
reaches a point where the ball of semi-dry dough (dry on the outside,
wet on the inside) clings to the hook and if there's lots of flour in
the bottom of the bowl, the ball spins around so that the hook
effectively does nothing. Alternatively, if the flour is added to the
liquid, it seems to be more difficult to get it to the "ball" stage....
...but what I'm thinking I should do is set it aside to hydrate for
20-30 mins before adding the final bit of flour - otherwise there's a
danger of adding too much flour at the beginning in an effort to get it
to "ball-up" properly so the kneading can begin.

Patrick