Sorry for the late reply, but I only just got here.
Im not the best at Lazarus/Pascal stuff but this isnt one of those questions,so...
The first colour picker is the windows one and in that one Saturation and Luminance only go up to 240 and Id say that the pascal one goes up to 255, so the slight differences. The hsl routine I was interested in recently did it as 0 to 1 values. Plus how you convert rgb to hsl can be done different ways. I recently looked at this and noticed it done a few ways, some consider saturation to affect lightness and some even considered some colours to have a lighter value than others.
For a colour picker you might want to offer 0-255, percentage and 0-1 and offer some way of copying the values, in the files Im using them for (Chrome Themes) their listed as h, s, l so maybe offer a comma seperator as an option
Plus the colours are listed that way in the themes as comma seperated rgb values. This way is also used sometimes in css files as something like rgba(0,0,0,0) so could be usefull for that aswell