I would like to have 2 company files opened at the same time
I agree with John - if you have 2 Hosted licenses or can get access to 2 hosted licenses - then you can run concurrent hosted sessions with different company files open - I do this all the time. Its one benefit of Hosted over Desktop. Its an individual choice as to how many licenses you wish to purchase. I often recommend to clients that they only purchase as many Hosted licenses as they really need to have users accessing at the same time - which means that often businesses can save money by purchasing less than they would have needed in the Desktop environment. From a technology point of view - I can understand why the login details can only be used in one instance at a time.