Yes, correct, but how do you explain the different names of your planets? In the Thalian system planets are named "Thala", "Thalia II", "Thalia III" etc and homestar "Thalis". There´s no "Thalia II II" or "Thalia II III"; as well as the PQ is fix, it doesn´t change... (anyway, it did change to the better to you, so nevermind....)
After following those instructions I had the same results - changing the homestar-tag in the .raceconfig-file @ the MyGames-folder to "Thalia II" will give you a system where planets are named "Thalia II II", "Thalia II III" etc, but observe the homestar is not "Thalis" but "Thalia II".
And later, the in-game changing of the homeworld-field to a world that does already exist in an original system will do the trick of giving you this extra planet - but that´s a thing that can be done in DL it´s not ARC.
Well, later on I´ve been told that ARC happens with the raceconfig.xml in the applications installation-folder, and NOT in the MyGames folder, but I didn´t pursue this anymore because my game did trip a flag (it´s been a ZYW submitted too early...)
But anyway I'm curious how you managed to get this PQ 19? On what raceconfig did you work actually?