It seems The Sims Team included more than 5 different heights of half-walls in The Sims 4. Sims 4 Studio member brujah was able to uncover 6 new half-wall sizes which are originally included in the game. According to the modder, this mod only “unlocks” these hidden wall heights. We tested it in our game and it works!
The new half-wall heights are marked with purple:
This mod can be downloaded by clicking the download button below. You can install this mod by extracting it to Electronic Arts > The Sims 4 > Mods. Make sure you have Mods / CC enabled in your game options!