Question about how are referees managed

Hello! I'm considering buying the premium version of this plugin, i'd like to know something first.

When you add a referee to a game, which I assume is from the staff management, will that referee get 'reserved' to that spot? In other words, when I create a new game, will I be able to select the referee and then be denied assignment if that referee is busy on another game at that time?

Also, I seem to be unable to purchase the premium version of the plugin. There's a message that says it will be available on December 2020, is there a specific day for the release?