How to edit a League to decrease the number of teams

Hi guys, as the title says, is there a way with the pregame editor to edit a League to decrease the number of teams that are in that league? For example, I wanna try and reduce the Italian Serie A to 16 teams, but if I edit the Advanced Rule and put the Maximun Club Number to 16 the editor says there are 20 teams and it requires 16, even if I put the flag on “Use for the next season”. Any Idea on how I can do it?