Thank you: you have revived my hope.
I bought the older (but essentially identical?) device from "spx" (model then called EL-50600).
It worked fine for a year or so, then I got worried by increasing warmth at connector to car, when I felt it right after a long charge session. Sent email to spx, and to Bosch, but got no response, so bought a different device with 20 A rating (LCS-25) to take its place. (It has lighter cable which gets slightly warm, but connector stays cool.) I had dropped the issue from "to do" list here.
Maybe I can get my old device back "up to speed", including slightly faster charging!
(No bet, here.)