If a client re-uses a connection to a VIP it would be more efficient than sending each HTTP request over a separate TCP connection. Similarly, if you use a OneConnect profile to have LTM re-use serverside TCP connections, it would be more efficient than LTM opening separate TCP connections for each HTTP request. I would assume the sizing numbers are best case estimates of what the platform can handle. Your actual experience will be highly dependent on the traffic patterns and client and server behavior. The best testing method is to simulate your user traffic patterns through LTM to the actual application you will be load balancing.
Aaron