"pool" number in the real time report is the current size of connection pool for that external application, is up to the "Max connections" configuration.
lsws dynamically adjust the pool size and keep the pool as small as possible. So, in your case, 2 is sufficient to handle all requests without any delay, even though, you thought there are 10 concurrent requests. ;-)
You can use "ab" to do some load test and check the pool size.