Non League Promotions/Relegations

I'm trying to sort my own promotion/relegation file out and wondering if anyone can help me.

It seems the 3 teams were relegated from National Prem - National North :

Halifax
Altrincham
Kidderminster

And 1 team was relegated to National South :

Welling

But according to Wikipedia, 2 teams got promoted for National North - National Prem :

Solihull
North Ferriby

And 2 teams from National South - National Prem :

Sutton
Maidstone

If that's correct then, according to my calculations then for the 2016/17 season the National North would consist of 23 teams and the National South 21 teams?

Usually what happens is that one team in the league with the most (so the North in this case) will get swapped into the south, but also depends on the promotions from below that could even it out.

Haven't seen an official announcement but wikipedia says this:

https://en.wikipedia.org/wiki/2016–17_National_League#National_League_North