I hope you prove it doesn't work, it would save me a couple hundred bucks per year.
I have three heads that had moldy head odor. If I washed the heads down, including floors, walls, etc, it would go away, so it was just wet humid non-ventilated mustiness. When I first tried it, I put it in one and not the others. Very noticeable difference, the head with the Kanberra smelled clean, the others continued to develop that mustiness. Not a population set large enough to satisfy the scientific method, but more than anecdotal.
I wrote to Kanberra to ask them to compare their product to others on the market and they gave me permission to post their reply in the thread I started on their product years ago. At the least, they were very responsive. They may indeed have what you are looking for.