Yes, this is unusual. But we know that our customers are very diverse and we want to make vvvv affordable to as many people as possible. Therefore we decided to charge you according to the size of your business.
Like this, financially more potent users support the use of vvvv by a more diverse crowd and make it possible for us to make vvvv free for education. This should allow the community of users to grow faster, which in turn is in the best interest of every single user.
Not sure which one to check? Describe us your situation via firstname.lastname@example.org and we'll figure it out together!