I'm happy to report that it DOES fix the focus stacking problem. I downloaded it on my laptop (no way will I put it on my Mac Pro until I know that it works properly). I tested it with a small stack of images I made in the field yesterday at the Oregon Coast (incredibly beautiful, warm, atypical day for the coast in October), and it WORKED!
I do not know what else is new that matters to me, but at least the stacking works for me (and I expect for everyone).
That all took them WAY too long both to acknowledge and to fix, but at least it appears to be ok. I'll wait a few more days before doing anything with my desktop.
Eric