I have a couple of ideas on the reason for the discrepancy in the value of throughput compared to what you expected.

The first concerns the intervention of the "delta delivery" algorithm in the case two consecutive updates have fields with the same value. Can this scenario apply to your .NET adapters?
The other is the possibility that you have a setting of <max_delay_millis> higher than the frequency with which you push updates.
Neither, however, would justify a difference in behavior in the case with 10 clients compared to the case with 100 clients.

Please, can you confirm us the value of the <max_delay_millis> parameter in use? And for the <delta_delivery> one?
If you prefer, send us the entire configuration file ("lightstreamer_conf.xml") in use in your test server and the server log of your tests with the logger ="LightstreamerMonitorText" set to TRACE level. You can also mail them to us at the support address.

Thank you.