It's comparable to the differences between, say, Activator and Activator Plus, Advance, Maxx,... . Or Superflex and SF Enhanced. PowerPlus and PP EX. Tweaks to change the reaction characteristics. Goo LS seems to be cleaner through the heads than Goo with more backend.
It is confusing and Track certainly doesn't go out of its way to identify what's solid, pearl, particle, or particle pearl, leading to even more confusion.
SH