What do you mean by " ‘perceptual’ studd (stuff)". The manual states that color balance RGB works “in a linear RGB color space [which] exhibits a uniform spacing of perceptual hues while retaining a physically-scaled luminance”. And at output colours can be pushed back into range by changing chroma and lightness at constant hue. So that should give the expected results here (within the limits of the colour spaces used…)
Keep in mind also that computer RGB values are usually display referred, and can represent very saturated colours. Those can easily get out of the range of valid colours when manipulated in another representation.
As an example, look at the limits of the sRBG colour space. There are colour spaces that are enough larger that you can “rotate” the ‘sRGB triangle’ as much as you want without getting outside that colour space. But you can’t then go back to sRGB and hope to have all your colours intact as you rotated them out of the range sRGB can present. (even a rotation of 1° in the shown plane is enough to lose some colours).