Seems strange that many people that play SC still believe EVERYONE in the game has to set latency in order for the game to completely have the specified latency. I disagree because i did my own research, you can do the steps below:
1) Get in a game with at least 1 other person
2) The game has low latency set by default, set it to extra high
3) Go back to the menu again, notice how the extra high option is now selected by default
4) Confirm with the other person that extra high is selected by default