Actually, to my ear, the line "Luke, we're ready for takeoff" is a different take in the '85 and '93. Billy Dee seems to place more emphasis on the syllable "off" than in the 70mm.

A lot of the confusion about the 70mm comes from the differences in the Super 8 digests (which used the 70mm cut as their picture source only) as well as the "Story of" LP, and of course the SE. We mistakenly assumed that these reflected an earlier mix, but now that we know that the 70mm mix is 99 percent identical to the 35mm, it means that these changes were made after the revised mix was locked.

In true Lucas fashion, he and Ben Burtt continued to tweak the mix after the revised cut was delivered, for the 8mm digests and Story LP. This period was the origin of many of the SE audio changes. Obviously, Lucas and Burtt preferred these alterations and documented them, because 16 years later, a lot of them made it into the SE. (Others didn't, like the different ADR takes for Han and Luke in the opening scene, or Leia's second "We have to go back!", or the 8mm's robotic voice and revised dialogue for the cloud car pilot.)

Also, is it right to call it 35mm vs. 70mm? Wouldn't the initial 35mm venues (drive-ins, I think) have also used this cut? Additionally, there are frames of the bacta shot among the collectible 70mm cells from the 90s (though I have a theory that these prints were made in the 90s, especially for those cells, and thus used the revised cut...)