The reason is fairly simple.

For the Platinum Level System, we allow our users to register more that one account with us to manage Design and Development Projects.(i.e. each member of the clients teams will be entitled to a user account to access the project management system, to manage your firms/business/companies project)

As such, most clients would allow their project team to access the Platinum Level System (Project Management System) whilst they are the only ones who’d be able to access the Support, Billing, Invoicing and Ordering Systems which carry more sensitive information. (i.e. Both you and your team would be able to access the Platinum Level System to manage your Project, but only you’d be able to access more sensitive systems and areas, such as Invoicing, Billing, Support Inquiries and Domain and Hosting Management.)