Realistically, there should be some spread between what the rental brokers pay out and what you can secure privately, because the broker handles both advertising as well as running interference between the renter (who may have zero idea how all of this works) and the owner. And given that private rentals here are going for 17-18, 12 is probably too low, but not completely insane.
The real question for me is how much the drop in broker payouts is due to softening demand, and how much an increase in supply. There have been a lot of people talking about buying to rent for the last year or two...