Hello @V50
The text "Teams promoted from lower division" is referring to teams promoted automatically from the league stage without going into the playoffs, which is correct in reading 0. Likewise the "Teams relegated from upper division" also reads 0, because no teams are automatically relegated via the league stage from the top division.
The "Teams relegated via upper division playoff" text refers to any additional teams relegated from the playoff more than the number of teams from the lower division who originally entered that playoff.
Basically, because you have set 10 teams to relegate from the playoff with only 8 coming into it from the lower division there is a shortfall of 2 teams for the upper division next season that would be fixed by either having 2 less relegated teams from the playoff or 2 more league promotions from the lower division.