The JSC is unique in that it utilizes a source separate from that of the 1993 Definitive Edition/2006 GOUT (possibly from a 1st generation interpositive of the O-Neg?), and yields substantially different colors and idiosyncrasies as a result.
IIRC the JSC is actually composed of two different prints spliced together. There are a few places where the last frame of a shot has different framing and colour balance to the previous frames, meaning a blanket correction of a unadjusted capture can be yeild inconsistent results over the whole film. I think the brightness level is higher to begin with too, at least compared to the other common widescreen laserdisc releases.