By default, sequences will "wait for responses" if the product file for that device contains a response.
You can change the behavior of the sequence to not "Wait For Device Responses" by clicking on the "Seq Options" button in WinScriptLive. Then, click on the "Time" tab and uncheck the box.
Take for example a TCP (Telnet) controlled device. In the background, your device requests will still be sent. However, it may still take a while for those requests to be processed if a new TCP connection needs to be established. Depending on the other device, TCP connections can sometimes take a while (usually 1-2 seconds).
In other words, not waiting for responses will speed up the other commands execution in the sequence but not the actual TCP connections and messages to your device.
The V16Pro will never close the connection, but sometimes devices do if there is no activity. It's best for the device to never close the connection. If you see a delay, make sure that connections are not being "dropped" by your device. You may have a sequence send a command (like getversion or something else that has no effect) to your device every few seconds to keep the connection alive.