"Always Active" means that your main account validity will always be extended to match the subscription validity of your biGBonus Plan.

For example, if your account validity expires tomorrow but you subscribe to a biGBonus Plan with "Always Active" feature today, your account validity will be extended by 30 days (instead of expiring tomorrow).
However, if your main account has a validity of more than 30 days at the point of subscription to a biGBonus Plan, it will remain unchanged.