This looked like an inexpensive way to do what I'm after, so I ordered a unit. However, the store owner (Randy at R/C Dude Hobbies) emailed me and said I ordered the last unit in stock, and when they tested it before shipping it, it was bad. So they canceled my order since they don't plan to restock.
However, in an incredible customer service move, he gave me a link to another store that still has them in stock, but at much lower prices! Here's the link he sent me:
https://www.allerc.com/advanced_search_result.php?keywords=emeter&x=0&y=0
I did order a unit and the accessories. Just in case anyone else is considering trying those units out, I thought I'd pass that info along.
Tony