46RH Slip Yoke Trouble

So this all got me thinking. I just checked the 3 '92 518s I've got out in the shop with a '98 46RE yoke, no go. Won't fit my '65 727 either (but we knew that). A '92 yoke fits fine, and the 727 as well. Same story for a couple 727 yokes when I tried them. I didn't check fit with the 727 style yoke on a 46re (didn't want to dig it out), but that's kind of irrelevant to this conversation anyway