This has been discussed many times elsewhere. The consensus seems to be – no, there’s no indication of there being an 85 mix for ESB and ROTJ of any sort, substantive or not. Minor differences reported from release to release are not inconsistent with the slight variation of a single mix applied over multiple releases.

Also AFAICT, there’s no content difference (i.e. different dialogue or effects) in the 93 mix of Jedi.

I know you’re probably collecting VHS tapes for some sentimental reason and there’s nothing wrong with that, but I do want to remind you that there are much, much, better ways out there to hear the 77/80/83/85/93 mixes.