Yes it's exactly that, i haven't had much time making clear instructions.
Actually you should have had the menu installed by then, without running the bat thought you wouldn't have any more than the standard 5 maps.
I am not aware of such an issue as i haven't encountered it. If you want you can hit me up on discord and we'll figure it out.
In order to import a bunch of maps instead of replacing the existing 5 over and over again i would suggest you use this menu script.
(This was created for Teardown v.04.6 and does not work for recently updated versions)