Gotta admit, that last screen form dear ben seems pretty contradictory from what he has been saying recently.
going from CE 3.7 ( star engine ) to 3.8 is a nono from your own words shown up there, but going from star engine ( modified 3.7 CE ) to lumberyard, ( modified 3.8 CE ) is easy peacy.
care to explain ?
I think I explained further up, but it's probably buried.
If your modifications are relative to 3.7, and their modifications start diverging at 3.8, then switching from "modded 3.7 CryEngine" to "modded 3.7 Lumberyard" is no changes, because you're at a point before theirs diverged.