This is a good question. Also curious about the promotion rules for D.IV into D.III.
256 D.III teams. 64 of those need to promote to fill D.II. Sounds like, on average, 4 teams from each D.III league will promote.
64 teams from D.III are promoting, and a minimum of 32 are demoting. Although I seem to recall a rumor saying their would still be hyper promotion/demotion between D.III and D.IV for another season.
There are 66 D.IV leagues with humans in them. Seems like either half of the D.IV Finalists that didn't win will promote, or a lot more teams are demoting from D.III.
Not sure about your maths.
If 64 teams promote out of DivIII and 32 demote that means that only 96 teams from Div IV will be promoting to Div III.
If there are 66 Div IV leagues I assume that means that the 66 winners from these leagues will promote and that there will be an additional 30 teams from across the 66 leagues that will also promote.
Im assuming that these extra 30 Div IV teams that are to promote will be the 30 teams (from across the 66 leagues) who had the best seasons records but failed to win their league championships.
Is this how it will work?