How does mairlist pick if: Use exact order, repeat if necessary is chosen?

I am trying to figure out how to create good music mix.
I have 5 music categories, and i have chosen: Use exact order, repeat if necessary
Then I have listed certain category order, but I don’t know how songs are picked from those folders (it is not explained in docs)
It feels like it is not randomly, as I get lot of repetition when it comes to artists from certain folder. Is artist and track separation implemented in this case?

You can generate a report as a txt-file while creating a playlist by the Mini Scheduler.
This file shows precisely which folders have been chosen in which order, how the titles are picked from them and how the playlist is created.