Okay, so I re-read the script more closely, all you have to do is set A3W_teamBalance = 1;
If you set A3W_teamBalance = 50, then it means team balance won't activate until the bigger team has reached 50% of total players, like in your screenshot. If you want team balance to be always active, then 1 is sufficient. That script won't activate below 15 total players anyway.