Once you have registered for All India Counselling for AIQ or State counselling, it is sufficient for all the rounds ie you will not have to register and pay the fees again, provided you attend the counselling. If you attend the counselling (irrespective of getting a college), you will automatically be eligible to attend the next round. Anyhow if you fail to attend any counselling (they require your signature or an authorized person's signature), you will not be allowed to attend further rounds of counselling.