iTunes Connect - Release time if app is set to specific launch date?
You can set only the date because it's impossible to release an app in a minute. From the pression of release button to effective global availability takes a few hour: there's the "preparation for the store" state which takes some minutes then your app start appearing in some stores all around the world but, if you try to get, you can get some errors then, in more or less 2-3 hours, it's stably on sale all around the world.

Same thing from prices change.

That's the history of an update of my app:


  Feb. 24, 2015 13:33      Me....      Waiting for review
  
  Mar. 03, 2015 08:35      Apple   In review 
  
  Mar. 03, 2015 09:40      Apple   Preparing for App Store
  
  Mar. 03, 2015 09:45      Apple   Ready for Sale


But it took a few hours more to be effective available...