By editing the script, you only changed the initialization value. Which means that if you didn't already have that variable in your vars_myname.txt file, it would use that value. However, evidently you do already have that variable saved, so it uses your saved value rather than the initialization value contained in the script. To edit these settings, you need to change the value in your vars_myname.txt file, which appeared in your scripts directory the first time you ran a script containing ZLib 3 or later.