the CSS will break the perisistence only if this is needed. For example, if you do stickyness on a cookie and the cookie changes to a different server, the CSS will then remap the connection to a new server.
In your case, wih no stickyness, the command 'no persistent' is useless.
The behavior that you see is normal.
Remapping the connection takes a lot of resources and is time consuming [you need to make a new 3-way tcp handshake, and close the connection with the previous server].
Moreover, with high number of connections the load will be spread accross all the servers anyway.
If your customer really wants each request to be splitted accross the servers, they should turn off HTTP/1.1 on their servers.
Gilles.