Yes, I am testing it and so far it works. I basically have a second window open, looking at the tables in phpMyadmin while I insert new Sub Categories. I do see 1 new single record in the main Sub Categories table, as it should be. And multiple related records in the relational table displaying the matching foreign key ID. Then, when I delete the Sub Category, it removes all records in both tables.
After hundreds of tests, not seeing the records removed from the relational table, I can't tell you how excited I was when I finally watched them disappear. I won't move this to the live site until I am sure, but so far so good.