There are license capabilities (what is being referred to here) and then there is what the appliance can realistically handle.
The SMB appliances do come with more Remote Access users (depends on model) and can be extended by another 50 users or so.
The amount you can extend it is, realistically, what those devices can handle.
Our non-SMB appliances only come with 5 Remote Access users.
If you want to do more than that, you can buy licenses to extend this (either Mobile Access or Endpoint depending on your specific requirements).
Mobile Access licenses come in three flavors: 50, 200, and Unlimited.
Obviously, no appliance will truly support "Unlimited" users as CPU and Bandwidth limits will come into play (internet bandwidth, bandwidth each user is using, access method, etc).
Under optimal conditions, a 3200 can support several hundred remote access users--more than the SMB appliances.
As I noted above, you should work with your local office or reseller to make sure the correct appliance is specified for your needs.