Sorry for being late, I've fixed the plugin.
The problem happened because of a space after the command: "newgame+ Test1 on" was accepted, but "newgame+ Test1 on " was not.
I've uploaded an updated version of the plugin.
I hope there will be no further bugs, but if there will be, I'll fix them (and I'll be quicker in the future — sorry!)
— Dmy