1) "Users: Unlimited" means that the number of users in one account is not limited.
You can have 100, 200, or even 300 users when you need it. We have several big clients and we understand that it is important for them that the number of users in one account is not limited.
2) The system generates a proforma-invoice when you wish to add a full user to your account. This is because our pricing is per user, and this information is also stated on the top of our price list.
Some of our competitors have pricing per account, but we found that pricing per user is more suitable for our clients. Several of our clients have confirmed that pricing per user is more convenient and more flexible.