"Interesting" is right. The ESB/ROTJ color timing is so strange to me, and especially ESB - the yellow-greenish look of the pre-THX transfers is so different from the examples I've seen of the original theatrical colors.

I cannot correct the colors for Empire to come anywhere near the original timing. They are so different that I'm starting to think that the pre-THX Empire/Jedi transfers were taken from new interpositives off the untimed negative, and timed completely differently, specifically to read better on home video. To me, they look even more unlike the original theatrical timing than the '82/'86 transfers of the first film.

(You know...maybe the statement about the "1985 IPs" refers to Empire and Jedi only? Empire debuted on video in 1985, Jedi in 1986, and the JSC releases were also in '86. AFAIK, these were the only NTSC transfers of the films until '93.)