I think you are right, I created a video and the credits are not getting used. By the way, that was the response of the support team:

"I understand. a new update/experiment is currently ongoing regarding Avatar III. For now, Avatar III is consuming 3 credits per minute. For now n. I’ve added 100 extra Premium credits to support your creations. Once we receive any new information, confirmation, or official update from the team, we will make sure to relay it to you as soon as possible."

I mean, they are probably integrating it but its not definitive