They state that they are going to send out bills to the Congregations for things like electricity due to the change of ownership.
What's the chance of them to start charging rent?
They were only too eager to charge them interest on the loans and made the congregations pay these loans back. Then they were made aware that they can't legally charge the interest and possibly loan the money as well.
They announced that they were lovingly 'forgiving' these loans in theory.
Now they want to own the Halls and since they own them, there's nothing to stop them from charging rent or even disguise that bill to the congregations as an 'allocation for future major renovations/repairs. Or maybe bill the congregation after renovations have been carried out. I doubt most Elders would think twice about it since they will be receiving bills from the Watchtower Trust anyway.